Project+2+-+Polygonal+Modeling





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=Setting modeling preferences=

Before you create your polygon model change some of the default settings to better work through this lesson.  > This displays border edges prominently on polygon meshes. Displaying border edges distinctively lets you differentiate them from other edges on your models and troubleshoot issues. > = = =**To load reference images into the front and side orthographic views**= > HelmetFront.jpg appears in the front view and depicts a drawing of the helmet.  Note  The front and side images for this lesson were created so that the two views are aligned and the height of each image is identical. When you import them as image planes, they appear at the same scale. These are important considerations when you construct your own reference images in the future. Otherwise, your reference images may not align or may be at different scales between the two orthographic views.
 * 1) Select Window > Settings/Preferences > Preferences . The Preferences window appears.
 * 2) In the Categories section of the Preferences window select Polygons.
 * 3) In the Polygon Display settings, set the following: 
 * Highlight: Border Edges : On
 * Edge Width : 4 [[image:Screen Shot 2012-12-18 at 12.51.28 PM.png]]
 * 1) In the Categories section of the Preferences window, choose Selection.
 * 1) In the Polygon Selection settings, set Select faces with to Whole face . The Whole face setting lets you select polygon faces by clicking anywhere on the face (the Center setting requires you to click on the face’s center dot). In addition, when a face is selected in the scene, the entire face appears highlighted.
 * 2) Click Save to close the settings window.
 * 3) Turn off the Interactive Creation option for primitives: Select Create > Polygon Primitives > Interactive Creation (no check mark).
 * 1) In the Toolbox, click the Four View shortcut [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-BABD113E-BA6B-4226-8FE6-8F0F7A133B13-low.png]] from the Layout Shortcuts bar or click a space bar. The perspective view is located in the top right corner and the other views show your scene from the top, front, and side.
 * 2) In the **front view** panel menu, select View > Image Plane > Import Image.
 * 3) [[image:Screen Shot 2012-12-18 at 1.04.47 PM.png width="236" height="209"]]
 * 4) In the browser that appears, select the image file named ** HelmetFront.jpg ,** and click Open . This image can be found on our website.
 * 1) In the side view panel menu, select View > Image Plane > Import Image.
 * 2) Select the image file named HelmetSide.jpg and click Open . HelmetSide.jpg appears in the side view.



= = =To create a cube primitive for the helmet mesh=

>  You can smooth the cube so it appears more rounded on the corners and subdivide it into smaller faces using the Smooth feature.
 * 1) Ensure you are working in the perspective view.
 * 2) Select Create > Polygon Primitives > Cube >[[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]].
 * 3) In the options window, select Edit > Reset Settings, and then set the following: 
 * Width : 14
 * Height : 14
 * Depth : 14
 * Width divisions : 1
 * Height divisions : 2
 * Depth divisions : 1
 * [[image:Screen Shot 2012-12-18 at 1.10.58 PM.png]]
 * 1) A cube primitive is created at the origin with the dimensions you specified and one subdivision around the middle. This cube primitive is comprised of four-sided polygon faces called //quads//. Quad polygons are used frequently with 3D character models as they are easily smoothed and deform well when bound into a skeleton.

 The polygon faces are still four-sided even though their shape and position have been modified by the smooth operation.  Note  If the top, domed portion of the smoothed cube doesn’t roughly match the helmet sketches as indicated in the image below, scale the cube with the Scale Tool to make it match.   <span class="anchor_wrapper"> To rename the polygon mesh
 * To smooth and subdivide the cube primitive**
 * 1) Make sure you are **on Polygons.** With the cube still selected in the scene view, select ** Mesh > Smooth > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]]**, and set the following options in the window that appears:
 * 2) [[image:mesh .png]]
 * Add divisions : Exponentially
 * Division levels : 2
 * 1) Click Smooth . [[image:Screen Shot 2012-12-18 at 1.33.12 PM.png]]
 * 2) The cube primitive is smoothed and is rounded at its corners. The cube has also been subdivided into smaller faces.
 * 1) With the cube still selected, rename the cube primitive from pCube1 to helmetmesh using the Channel Box.

> <span class="anchor_wrapper"> <span class="anchor_wrapper"> The opacity of the smooth shading in the side and front views prevents you from seeing the image planes behind the object. X-Ray display mode solves this problem by making the smooth shaded surface appear semitransparent. =<span class="anchor_wrapper"> = =<span class="anchor_wrapper"> To display the helmet mesh in shaded X-Ray mode=
 * To display the helmet mesh in Wireframe on Shaded mode**
 * 1) In the perspective view, right-click on the helmet mesh and select Object Mode from the marking menu that appears.<span class="anchor_wrapper"> This changes the selection mode to Objects.
 * 2) [[image:Screen Shot 2012-12-18 at 2.18.48 PM.png width="345" height="339"]]
 * 3) Select the helmet mesh.
 * 4) In the perspective view, select Shading > Smooth Shade All from the panel menu.<span class="anchor_wrapper"> The helmet mesh displays in smooth shaded mode. [[image:Screen Shot 2012-12-18 at 2.22.07 PM.png]]
 * 5) From the panel menu, select Shading > Wireframe on Shaded .<span class="anchor_wrapper"> The wireframe appears on the mesh as well as the shading (whether or not the mesh is selected).

> <span class="anchor_wrapper"> The helmet mesh updates to a semitransparent shaded display with the wireframe. You can see the 2D image behind the mesh. <span class="anchor_wrapper"> After setting the shading for the objects in the various views, you may wish to adjust the Alpha Gain setting on your image planes to change their transparency. As you gain experience with Maya, you’ll develop your own personal preferences for modeling in wireframe or shaded mode and switching between the various shading modes. > > **To delete the faces on the left half of the mesh** > > 1. In the top view, right-click on the mesh and select Face from the marking menu that appears. > > 2. Drag a bounding box around the faces on the left half of the helmet mesh to select them. > > 3. Press the delete key. > > The selected faces are deleted. > > You now have half as many components in your model. When you near the completion point of the model, you will copy the finished half across the axis of symmetry to get the complete model.
 * 1) With the helmet still selected, choose the following from the side view’s panel menu:<span class="anchor_wrapper">
 * Shading > Smooth Shade All
 * Shading > Wireframe on Shaded
 * Shading > X-Ray.
 * [[image:Screen Shot 2012-12-18 at 2.23.48 PM.png]]
 * 1) Repeat the previous step for the front view as well.<span class="anchor_wrapper">

=**To select faces for deletion using the Paint Selection Tool **= Note: The Paint Selection Tool only selects components on the mesh that face towards the camera.
 * 1) In the Toolbox, click the Paint Selection Tool icon.
 * 1) In the side view, right-click the helmet mesh and select Face from the marking menu that appears.
 * 2) In the side view, paint select the faces that appear along the front and lower areas of the mesh (see image) by dragging the mouse over the faces. Use **Shift** to select or deselect faces.

> > The rows of edges immediately above and below the X axis referred to as //edge loops//. **An //edge loop//** is a path of polygon edges that are connected in sequence by their shared vertices. Edge loop selections are very useful when you model using polygons. > **To align edges on the helmet mesh**
 * 1) Press the delete key to delete the selected faces.
 * 2) Tumble the perspective view to review your work so far. The edges that reside along the outside perimeter of a polygon mesh, called //border edges//, are displayed with a thicker line than the interior edges on the mesh. You set this display setting early in the lesson so you could differentiate this edge type from other edges.
 * 1) Right-click the mesh and select Edge from the marking menu that appears. Maya’s component selection mode is set to edges. [[image:Screen Shot 2012-12-19 at 8.50.16 AM.png width="232" height="298"]]
 * 2) Double-click one **edge in the edge-loop directly below the X-axis**. The edge loop is selected.
 * 3) [[image:Screen Shot 2012-12-19 at 8.55.37 AM.png]]
 * 4) On the Status Line, turn on the Snap to Grids feature by clicking the icon.

Snap to Grids lets you move selected components to the closest grid line or grid intersection point. When many components are selected, you can align them to each other via the grid simultaneously. >> <span class="anchor_wrapper">
 * 1) In the Toolbox, double-click the Move Tool to display its tool settings.
 * Close the Tool Settings window. **
 * 1) In the top view, click-drag the blue arrow on the Move Tool manipulator downwards a small distance. The edge loop immediately snaps to a lower grid line. It is not positioned at the location you want, but all of the edges in the loop you selected are now aligned to each other.
 * 2) On the Status Line, turn off the Snap to Grids feature by clicking its icon.
 * 3) With the Move Tool still active in the top view, drag the manipulator arrow upwards a short distance so the edge loop is positioned roughly at its original location (which should be at the second grid line below the X-axis).
 * 4) Using the steps described above, align the other edge loop that appears above the X-axis and then align the edge loop directly to the right of the Z-axis.<span class="anchor_wrapper"> When you have finished, the edge loops nearest the X and Z axes are aligned. (see image below)
 * 1) IF THE INSTRUCTIONS FOR STEPS 1-4 DON'T WORK, YOU CAN ALIGN THESE X AND Z AXES BY INDIVIDUALLY SELECTING THEM WITH SHIFT KEY AND SNAPPING TO THE GRID. MAKE SURE THAT YOUR LINES LOOK LIKE LINES BELOW.


 * To manually reposition the vertices on the rear of the helmet**
 * 1) In the side view, right-click the helmet and select Vertex from the marking menu that appears.
 * 2) Select the pair of vertices at the rear lower edge (see image) by dragging a bounding box around them.
 * 3) In the Toolbox, click the Move Tool.
 * 4) In the side view, click-drag the blue arrow on the Move Tool manipulator towards the right until the vertices are repositioned so that your helmet matches the reference sketch on the image plane. <span class="anchor_wrapper">

By moving the vertex as well as the vertex adjacent to it along the axis of symmetry, you ensure that the symmetrical shape of the helmet is maintained. If you move one vertex independently of the other it may result in an unwanted bump or valley in the mesh. These types of anomalies will become more apparent when you copy the completed half of the mesh across the axis of symmetry. <span class="anchor_wrapper"> Tip <span class="anchor_wrapper"> You can click in the center of the Move Tool manipulator to drag a vertex selection freely. <span class="anchor_wrapper">
 * 1) Repeat steps 2 through 4 for the other pairs of vertices on the rear of the helmet. Ensure that the edge loops appear smooth in relation to each other. When you have finished, the back region of the helmet should closely match the reference image on your image plane.
 * 1) In the side view, select other pairs of vertices along the top and front of the helmet and move them in a similar fashion so they match the reference image. Do not reposition the vertices for the top of the face shield yet.
 * 1) Move the vertices in the front half of the helmet above the face shield upward. <span class="anchor_wrapper">

Next, you’ll reposition the border edges that lie along the bottom edge of the mesh. You can select these edge types using the Select Border Edge Tool.

Note Up to this point in the lesson, you’ve been instructed to reposition the vertices on the helmet mesh only within the side view (Y, Z plane). Once you achieve the shape you want in the side view you will then concentrate on how the model appears when viewed from the front and perspective views.
 * To reposition the lower border edges on the helmet**
 * 1) In the side view, select the lowest horizontal edge loop on the helmet by choosing Select > Select Border Edge Tool from the main menu, and then clicking the first and then the last edge on the loop as indicated in the image below.
 * 2) Using the Move Tool, drag the selected edge loop downwards until the left hand vertex roughly matches the lower edge indicated in the reference sketch. <span class="anchor_wrapper">
 * 1) In the side view, select and reposition the remaining vertices individually on the edge loop using the Move Tool so they match the reference sketch. <span class="anchor_wrapper">

<span class="anchor_wrapper"> Note: You may need to move the position of vertices in the upper part of the helmet before you move the border edges.
 * To edit the border edges on the upper edge of the face shield**
 * 1) From the Select menu, choose Select Border Edge Tool.
 * 2) In the side view, click the first border edge that will be used as the upper edge of the face shield, then click the last border edge (see image).
 * 3) The border edges in between are selected.
 * 1) In the Toolbox, select the Rotate Tool by clicking its icon.
 * 2) In the side view, click-drag the rotate manipulator in a clockwise direction until the border edges are rotated at roughly the same angle as the corresponding edge in the reference sketch. <span class="anchor_wrapper">
 * 1) With the border edges still selected, click the Move Tool again and drag the green manipulator upwards to match the location of the border edges in the reference sketch. <span class="anchor_wrapper">
 * 1) Reposition the pairs of vertices on the upper front of the helmet to match the reference sketch.

At this point in the lesson, the outline of your helmet should roughly match the helmet in the side view reference image. If it doesn’t, review the earlier steps in this lesson and make any adjustments to your polygonal mesh as required.

If you view your helmet in the front orthographic view, you’ll notice that the helmet shows a wider profile from this view than the reference sketch. In the next steps you’ll correct this using the front and top orthographic views of the helmet for reference.

To reposition vertices on the side of the helmet to match the sketch
 * 1) Display the front view.
 * 2) Right-click the mesh and select Vertex from the marking menu that appears.
 * 3) In the front view, select the vertices that extend beyond the outline of the helmet as shown in the reference sketch (see image). <span class="anchor_wrapper">
 * 1) In the front view, move these vertices to the left until they match the widest area of the helmet in the reference sketch (see image). <span class="anchor_wrapper">

When you view your helmet from **the top orthographic** view the region between the side and rear of the helmet appears a bit flat in relation to the other areas.

To correct this you can move the other vertices in this region outwards in a similar fashion so the curvature in this area appears fuller and more rounded. However, viewing only from the orthographic views can be limiting, and you should also use the perspective view to examine the mesh.

To examine the mesh using the perspective view As you examine the vertices along any particular edge loop, the vertices on the mesh should appear to cascade in a smooth gradual fashion to create the curvature of the mesh with no undesirable spikes or dips.
 * 1) Enlarge the perspective view.
 * 2) Dolly and tumble the perspective view while you closely examine the helmet mesh.

Ensuring that the mesh appears relatively smooth at various stages throughout the modeling process will reduce the possibility for issues when you create a high resolution version of the mesh later on.

If you find areas where one vertex (or more) appears to protrude outwards (or recedes) on the mesh in relation to neighboring vertices, you can correct these protruding regions by repositioning the affected vertices in the perspective view.



> <span class="anchor_wrapper"> <span class="anchor_wrapper"> The U and V handles slide the vertex in relation to its associated edges, while the N handle moves the vertex either away or towards the mesh depending on the direction you move your mouse. <span class="anchor_wrapper"> If you examine your model in the perspective view your helmet mesh should now match the reference sketches as they appear in both the front and side image planes (see image below). The mesh should also have a relatively uniform distribution of polygon faces on the mesh and the edge loops should flow smoothly. <span class="anchor_wrapper">
 * To move a vertex on the mesh in a direction normal to the mesh**
 * 1) Dolly and tumble the perspective view while examining the mesh until you find vertices that protrude outwards from the mesh in an unwanted fashion.
 * 1) In the Toolbox, double-click the Move Tool to display the Move Settings editor.
 * 2) In the Move Settings editor, in the Move section, turn on the Normal option.<span class="anchor_wrapper">
 * 1) In the perspective view, click the vertex you wish to reposition.<span class="anchor_wrapper"> The vertex highlights and the Move manipulator appears to indicate the three directions of movement that are possible in this mode.
 * 1) Drag the N handle outwards or inwards depending on what’s required for that particular vertex. Dolly or tumble the view as required to examine the mesh after you’ve done this and make any modifications as necessary.
 * 2) Repeat the above steps for any other protruding or receding vertices on the mesh until you are satisfied that the mesh appears smooth.
 * 3) Before you proceed to the next section, double-click on the Move Tool and return the Move setting to the default World setting.

> <span class="anchor_wrapper"> These settings specify that a closed polygon face will be created once you have placed six vertices in the scene. <span class="anchor_wrapper"> The new polygon face is created along the YZ plane (the axis of symmetry for the model). > <span class="anchor_wrapper"> > <span class="anchor_wrapper"> Note <span class="anchor_wrapper"> If the polygon face doesn’t appear shaded in the side view but does appear shaded in the perspective view, it means that the polygon face and the image plane lie on exactly the same plane. You can correct this by moving the image plane backwards in the side view so it doesn’t lie directly on the YZ plane, but this step is not critical to the success of the steps that follow. <span class="anchor_wrapper"> You’ll extrude this polygon face to create the remainder of the lower front region of the helmet. Before you can extrude the new face it needs to be selected in Face mode. You can do this quickly by converting the existing selection to Faces. <span class="anchor_wrapper"> > <span class="anchor_wrapper"> Tip <span class="anchor_wrapper"> You can also press Ctrl + F11 or Ctrl + right-click on the selected object and choose To Faces > To Faces from the marking menu that appears. > > > To extrude the polygon face for the lower front region >> <span class="anchor_wrapper"> <span class="anchor_wrapper"> > <span class="anchor_wrapper"> To delete unwanted faces on the extruded mesh <span class="anchor_wrapper"> When you are finished, a gap will exist between the last extruded segment of the lower region and the helmet mesh. >> <span class="anchor_wrapper"> <span class="anchor_wrapper"> You’ll combine these separate meshes together and then create a mesh that bridges between them in the next section of the lesson. To prepare for the bridge, you need to extrude more edges on the helmet mesh so that the number of edges match when you create the bridge. > <span class="anchor_wrapper"> > <span class="anchor_wrapper"> To extrude the bottom edges of the helmet mesh <span class="anchor_wrapper"> > <span class="anchor_wrapper"> To extrude top and side edges for the face shield <span class="anchor_wrapper"> > <span class="anchor_wrapper"> To move vertices on the lower front region to match the reference sketch To insert edge loops on the side region of the helmet <span class="anchor_wrapper"> <span class="anchor_wrapper"> >> <span class="anchor_wrapper"> To bridge between the lower front and side region of the helmet <span class="anchor_wrapper"> <span class="anchor_wrapper"> To prepare for the next part of the tutorial, open the Helmet3.mb scene ( File > Open Scene ) or continue working with the current scene.
 * To place vertices for a polygon**
 * 1) In the side view, select Mesh > Create Polygon Tool > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]].<span class="anchor_wrapper"> The Create Polygon Tool settings editor appears.
 * 2) In the tool settings editor, set the following options: <span class="anchor_wrapper">
 * Limit the number of points : On
 * Limit points to : 6
 * 1) In the side view, place six points for the profile in the lower front region of the helmet (see image below).<span class="anchor_wrapper"> Important Ensure that you place the vertices in a counter-clockwise direction for this step.
 * 1) Press the q key to quit the Create Polygon Tool when the polygon face is complete.<span class="anchor_wrapper"> The new polygon component remains selected in Object Mode.
 * <span class="anchor_wrapper"> To convert the object selection to face selection**
 * 1) With the face still active in Object Mode, choose Select > Convert Selection > To Faces .<span class="anchor_wrapper"> The selection is converted to a face selection.
 * 1) Enlarge the scene view to a single perspective view.
 * 2) With the polygon face still selected, choose Edit Mesh > Extrude .<span class="anchor_wrapper"> The extrude manipulator appears on the selected face.
 * 3) In the perspective view, enter a value of 1.5 into the Thickness field to extrude a section of mesh: <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_extrudelow1.png]]
 * 4) Press the g key to extrude again.
 * 5) Enter a value of 2.0 in the Thickness field.
 * 6) Click the large blue circle that surrounds the manipulator to display the rotate manipulators and then drag the green circular manipulator to rotate the angle of the extrusion to match the angle in the reference sketch (see image). You can also open the Channel Box and set Local Rotate Y to -26.
 * 7) Press the g key once again to create a third extruded region.
 * 8) Enter a value of 3.0 in the Thickness field.
 * 9) Enter the following values in the Channel Box to adjust the angle of the extrusion: <span class="anchor_wrapper">
 * Local Rotate X : 12
 * Local Rotate Y : -30
 * Local Rotate Z : 16
 * Local Scale X : 0.5
 * Local Scale Y : 1
 * Local Scale Z : 1.3
 * 1) You may also want to view the extrusion from either the front or side view to ensure your extrusion doesn’t extend outwards more than the side region. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_extrudelow6.png]]
 * 2) Save your work.
 * 1) Tumble the perspective view until you can view the inside of the lower front region (see image below).
 * 2) Select the faces that appear on the inside of the mesh you just extruded, including the faces on either end of the extrusion.<span class="anchor_wrapper"> These faces were required for creating the extruded portions of the lower region but are not needed beyond this point.
 * 3) Press the Delete key to delete the selected faces. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_deleteinside1.png]]
 * 1) In the perspective view, select the lower edges of the helmet mesh using Select > Select Border Edge Tool.
 * 2) Select Edit Mesh > Extrude, then enter a value of -1.0 in the Thickness field that appears. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_extrudebottom1.png]]
 * 1) In the perspective view, select the upper and side edges on the helmet mesh using Select > Select Border Edge Tool (see image below).
 * 2) Select Edit Mesh > Extrude and then enter a value of -1.0 in the Thickness field that appears. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_extrudeupperedge1.png]]
 * 1) In the perspective view, right-click on the helmet and select vertex mode to change the selection type to vertices.
 * 2) Select the four vertices on the lower front region of the helmet that are near the axis of symmetry (see image below) and using the Move Tool, move the selected vertices upwards by dragging the green arrow on the Move Tool manipulator so that the lower front region of the helmet matches the reference sketches as they appear in the various orthographic views. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_matchmouthregion1.png]]
 * 1) Select Edit Mesh > Insert Edge Loop Tool > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]].<span class="anchor_wrapper"> The Insert Edge Loop Tool settings editor appears.
 * 2) In the tool settings editor, set Maintain Position to Relative distance from edge.
 * 3) In the perspective view, click-drag the edge on the side region of the helmet near the bottom of the edge as indicated in the image below. Without releasing the mouse button, drag the mouse upwards about one third of the distance along the edge and then release the mouse button to insert the edge loop.<span class="anchor_wrapper"> Note <span class="anchor_wrapper"> Click-dragging an edge when using the Relative option inserts an edge loop that closely matches the existing edge layout on the mesh. That is, the lower region of the mesh is much wider near the front than at the rear. The Relative setting adjusts the position of the edge loop locator based on this topology so is ideal in these situations. When you click-drag using the Relative option, remember to click near the edge whose layout you want the edge loop to match.
 * 1) With the Insert Edge Loop Tool still active, click-drag the side region of the helmet near the top of the same edge and insert a second edge loop about two thirds of the distance along the edge. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_insertloop3.png]]
 * 2) Press the q key to return to selection mode, and click anywhere off the mesh to unselect the edges.<span class="anchor_wrapper"> Now that you’ve inserted the necessary edges, you can proceed with creating the bridge.
 * 1) Choose Select > Select Border Edge Tool and then click the border edges on both the lower front as well as the side region of the mesh where you want the bridging mesh to be constructed. (You should have five edges selected on either side).<span class="anchor_wrapper"> Tip <span class="anchor_wrapper"> When you select border edges using the Select Border Edge Tool you can click on the first and last edge in a series on one side of the bridge and the tool will select the edges in between.
 * 1) Select Edit Mesh > Bridge > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]].
 * 2) In the Bridge Options window, set the Divisions to 0, then click the Bridge button to create the bridge. <span class="anchor_wrapper"> [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/comp_polyhelmet_bridge2.png]]
 * 3) Press the q key to return to select mode, and click anywhere off the mesh to unselect the edges.<span class="anchor_wrapper"> Note If your bridge appears to twist or cross over itself it indicates that the two meshes have their surface normals mismatched. In this particular case it likely indicates that you did not create the original profile shape for the lower front by placing the six vertices in a counter-clockwise direction.<span class="anchor_wrapper"> If this occurs you must undo your steps to the point immediately before you combined the two meshes and then reverse the surface normals on only the lower front section by selecting it and then selecting Normals > Reverse . You can then redo the instructions in this section as required.

To create the face shield using the Append to Polygon Tool > <span class="anchor_wrapper"> If the planar option is on, the Append to Polygon Tool will not create a multi-sided polygon as the edges you’ll select do not form a planar region. > <span class="anchor_wrapper"> > <span class="anchor_wrapper"> <span class="anchor_wrapper"> Ideally, all faces should be four-sided to match the other faces on the helmet mesh. In the next section, you'll split the n-gon vertically and horizontally into several smaller four-sided polygons using the Split Polygon Tool.
 * 1) Tumble the perspective view so you can see all of the edges surrounding the area for the face shield.
 * 2) Select Edit Mesh > Append to Polygon Tool > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]].
 * 3) In the Append to Polygon Tool settings window, set the following: <span class="anchor_wrapper">
 * Keep new faces planar : Off
 * 1) In the perspective view, click once on the top inner border edge of the helmet mesh to indicate which mesh you are appending to, and then click the same edge a second time to begin the append operation (see image below).
 * 2) Click the bottom edge of the face shield that is opposite the first edge you just clicked.<span class="anchor_wrapper"> A polygon appears that spans the two edges.
 * 1) Continue to click the remaining border edges in a counter-clockwise direction around the opening for the face shield until you reach the last edge. <span class="anchor_wrapper">
 * 1) When you are finished clicking the perimeter border edges for the face shield, press the q key to quit the tool.<span class="anchor_wrapper"> The multi-sided polygon is completed and added to the existing mesh. Multi-sided polygons are also referred to as //n-gons//.

To split the face shield vertically <span class="anchor_wrapper"> When you are finished the n-gon for the face shield will be split into four new polygons. <span class="anchor_wrapper"> You can also split the face shield horizontally. This will give you more control over its shape afterwards. <span class="anchor_wrapper"> <span class="anchor_wrapper"> To split the face shield horizontally <span class="anchor_wrapper"> Note <span class="anchor_wrapper"> When you split across multiple faces at the same time you only need to click an edge to indicate the start point for the split and on a second edge to indicate the end point. The Interactive Split Tool automatically splits the edges in between. <span class="anchor_wrapper"> In the next steps you'll reposition some of the vertices along the horizontal split to make the face shield protrude outwards a small amount. <span class="anchor_wrapper"> <span class="anchor_wrapper"> To adjust the shape of the face shield <span class="anchor_wrapper"> Tip <span class="anchor_wrapper"> Tumble the perspective view so you can see the relationship between the vertices as you move them outwards. <span class="anchor_wrapper"> To create the diagonal grill vents on the lower front of the helmet you’ll insert edges on the face, reposition some of the vertices, and then extrude some of the faces. <span class="anchor_wrapper"> <span class="anchor_wrapper"> To insert multiple edges for the diagonal grill vents > <span class="anchor_wrapper"> These settings let you insert four evenly spaced edges on the face where you want the grill vents to appear. <span class="anchor_wrapper"> To make the grill vents appear diagonally you’ll select the vertices on the right side and then slide them downwards using the Move Tool. <span class="anchor_wrapper"> <span class="anchor_wrapper"> To move vertices along an edge using the Move Tool <span class="anchor_wrapper"> Note <span class="anchor_wrapper"> Make sure you do not move the vertices so that the lowest vertex touches the corner vertices or you’ll create an edge that has zero length. <span class="anchor_wrapper"> To make the grill vents three-dimensional, you’ll extrude some of the thin diagonal faces inwards. <span class="anchor_wrapper"> <span class="anchor_wrapper"> To extrude the faces for the grill feature <span class="anchor_wrapper"> To prepare for the next part of the tutorial, open the Helmet4.mb scene ( File > Open Scene ) or continue working with the current scene.
 * 1) Select the helmet mesh.
 * 2) Select Edit Mesh > Interactive Split Tool.
 * 3) Tumble the camera in the perspective view so you can view both the upper inner edges of the face shield as well as the lower inner edges.
 * 4) Click the top inner edge of the face shield to indicate the start of the split (see image below).
 * 5) Click on the lower inner edge of the helmet mesh to indicate the end of the split (see image). <span class="anchor_wrapper">
 * 1) Press the y key to split the face.
 * 2) Continue to split the face shield vertically at the other locations specified in the image below. Remember to press the y key after each split. <span class="anchor_wrapper">
 * 1) In the perspective view, with the Interactive Split Tool still active, click the inner side edge (see image) to indicate the start location for the horizontal split.
 * 2) In the side view, click the front vertical border edge of the face shield (this border edge lies on the axis of symmetry) and release the mouse button at the mid-point along the edge where the vertex naturally snaps (as if a magnet were attracting it towards that location). <span class="anchor_wrapper">
 * 1) In the perspective view, rotate the helmet and click its back vertical border. <span class="anchor_wrapper">
 * 1) Press the y key to split the faces. <span class="anchor_wrapper">
 * 1) Press the q key to quit the Interactive Split Tool.
 * 1) In the side view, select the middle two vertices at the front of the face shield and use the Move Tool to move the vertices outwards (+Z) a small amount (see image). <span class="anchor_wrapper">
 * 1) In the perspective view, select the remaining middle vertices on the face shield one at a time and reposition them outwards a small distance using the Move Tool with the Move Setting option set to Normal . <span class="anchor_wrapper">
 * 1) Reset the Move Tool 's Move Settings to World before continuing to the next steps.
 * 1) Select Edit Mesh > Insert Edge Loop Tool > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]].
 * 2) In the Insert Edge Loop Tool Options window, set the following: <span class="anchor_wrapper">
 * Multiple Edge Loops : On
 * Number of edge loops : 4
 * Auto Complete : Off
 * 1) In the perspective view, click the border edge of the face where the grill vents will appear and then click the edge directly opposite that border edge (see image). <span class="anchor_wrapper">
 * 1) Press the y key to complete the edge loop insertion
 * 2) Click off the mesh to deselect the edges.
 * 3) Press the q key to exit the tool and return to selection mode.
 * 1) Right-click the helmet mesh and change the selection mode to Vertex.
 * 2) Select the vertices on the right side of the grill feature (see image below). <span class="anchor_wrapper">
 * 1) Double-click the Move Tool icon to display the Move Tool ’s settings editor.
 * 2) In the Move Tool s’ settings editor, click the Set to Edge button.<span class="anchor_wrapper"> The vertices appear unselected temporarily. The Move Tool expects you to select an edge it will reference for the axis of movement.
 * 3) Click an edge that is on the same line of the edges as the vertices you selected.<span class="anchor_wrapper"> The Move Tool manipulator appears and is aligned to the edge you selected. The vertices appear selected again indicating that the Move Tool is now set to move those vertices along the axis defined by the edge you selected.
 * 4) Drag the red arrow on the Move manipulator downwards to move the vertices so that the shape of the faces for the grill are more diagonal (see image). <span class="anchor_wrapper">
 * 1) Click off the mesh to deselect the vertices.
 * 2) Before proceeding to the next section, double-click the Move Tool and reset the tool settings by clicking the Reset Tool button.
 * 1) Right-click the helmet mesh and change the selection mode to Face.
 * 2) Beginning at the bottom of the grill feature, shift-select the two diagonal faces as indicated in the image below. <span class="anchor_wrapper">
 * 1) Select Edit Mesh > Extrude .<span class="anchor_wrapper"> The Extrude manipulator appears.
 * 2) Drag the blue arrow on the Extrude manipulator towards the helmet a short distance to create the two recessed vents for the grill. <span class="anchor_wrapper">
 * 1) Press the q key to quit the Extrude feature.
 * 2) Shift-select the two side faces on the grill vents that lie on the axis of symmetry and delete them (see image below). These faces will not be required when you create the opposite half of the helmet. <span class="anchor_wrapper">
 * 1) Save your work before proceeding to the next section.

To manually split the multi-sided polygon into three four-sided polygons
 * 1) Select Edit Mesh > Interactive Split Tool.
 * 2) In the perspective view, click-drag on the top side edge of the top grill vent. Drag your mouse so the vertex is positioned at the bottom of the edge (see image). <span class="anchor_wrapper">
 * 1) Click-drag on the top edge of the multi-sided polygon and slide the vertex to the right end of the edge (see image).
 * 2) Press the y key to split the face.<span class="anchor_wrapper"> The region above the split edge appears like a polygon but is actually four-sided because of the edges on the grill vent.
 * 3) Split the side edge on the bottom grill vent in a similar fashion by click-dragging your mouse so the vertex is positioned at the top of the edge (see image below). <span class="anchor_wrapper">
 * 1) Click-drag the bottom edge of the multi-sided polygon and slide the vertex to the right end of the edge (see image).
 * 2) Press the y key to split the face.<span class="anchor_wrapper"> Your multi-sided face is now split into three four-sided faces, maintaining the overall quad topology on the helmet mesh.
 * 3) Press the q key to exit the Interactive Split Tool.

> <span class="anchor_wrapper">
 * To delete the construction history on the helmet mesh**
 * 1) Right-click the mesh and change the selection mode to Object Mode, and select the helmet mesh.
 * 2) Display the Channel Box if it isn’t already, and notice the list of history nodes that appear in the Inputs section.
 * 3) Select Edit > Delete History .<span class="anchor_wrapper"> The construction history is deleted on the helmet mesh. Notice the list of items under Inputs has only one item remaining—the polySurfaceShape node.
 * 1) Save your work before proceeding to the next section.

To ensure that the border vertices lie along the axis of symmetry <span class="anchor_wrapper"> Note <span class="anchor_wrapper"> Any vertices that protrude across the Y-axis likely occurred as a result of an earlier extrude operation. Because the extrude feature extrudes components based on the face normal, a few vertices may have moved across the axis of symmetry. <span class="anchor_wrapper"> > <span class="anchor_wrapper"> The mesh is copied along -X to create the opposite half of the model. The two meshes are combined into one and vertices are merged so they become shared. > <span class="anchor_wrapper"> <span class="anchor_wrapper"> At this point, the low resolution version of the helmet model is complete. In the next section you’ll preview how the model appears at a higher resolution using the Subdiv Proxy feature.
 * 1) Enlarge the front view so you can view the vertices that lie along the axis of symmetry.<span class="anchor_wrapper"> If any vertices on the mesh protrude across the Y-axis, you’ll need to snap these to the Y-axis using the Move Tool in combination with the Snap to grids feature.
 * 1) In the front view, select all of the vertices that should lie along the axis of symmetry (Y-axis) using a bounding box selection.
 * 2) On the Status Line, turn on Snap to Grids.
 * 3) In the Toolbox, double-click the Move Tool to display its tool settings and ensure that the Retain component spacing setting is turned off.
 * 4) In the front view, drag the red arrow on the Move Tool manipulator to the right a small distance.<span class="anchor_wrapper"> The vertices immediately snap to the grid line to the right. They initially will not be positioned at the location you want, but you’ll notice that all of the vertices you selected are now aligned to each other.
 * 5) Drag the manipulator towards the left until the vertices snap to the Y-axis. <span class="anchor_wrapper">
 * 1) On the Status Line, turn off Snap to Grids.
 * 2) Click off the mesh to unselect the vertices.
 * <span class="anchor_wrapper"> To mirror copy the polygon mesh**
 * 1) Right-click the mesh, change the selection mode to Object Mode, and then select the helmet mesh.
 * 2) Select Mesh > Mirror Geometry >[[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]], set the following options, and then click the Mirror button. <span class="anchor_wrapper">
 * Mirror Direction : -X
 * Merge with the original : On
 * Merge vertices : On
 * 1) Save your work before proceeding to the next section.

To create a high resolution smoothed model using Subdiv Proxy <span class="anchor_wrapper"> Note <span class="anchor_wrapper"> The two versions of the model are also grouped into the same node hierarchy when the Subdiv Proxy operation is performed. <span class="anchor_wrapper"> > <span class="anchor_wrapper">
 * 1) Right-click the mesh, change the selection mode to Object Mode, and then select the helmet mesh.
 * 2) Select Proxy > Subdiv Proxy > [[image:http://download.autodesk.com/us/maya/maya2013_getting_started/images/GUID-96432FB8-EBE9-4D1A-8DED-5173E032EBC0-low.png]], and set the following: <span class="anchor_wrapper">
 * Division Levels : 2
 * Mirror Behavior : None
 * Subdiv Proxy Shader : Keep
 * 1) Click the Smooth button.<span class="anchor_wrapper"> A higher resolution, smoothed copy of the helmet mesh is created in the same position as the original mesh. It is possible to see the two versions in this position (and you can toggle the display to show either or both) but in this lesson you’ll select the high resolution version and move it slightly to the left.
 * 1) Select only the smoothed version of the mesh in Object Mode and move it to the left about 25 units (X = -25).<span class="anchor_wrapper"> As you edit the low resolution version of the helmet mesh you’ll see the resulting updates on the smoothed version beside it.

To display hard and soft edges on a mesh > <span class="anchor_wrapper"> <span class="anchor_wrapper"> <span class="anchor_wrapper"> To soften the edges on the mesh <span class="anchor_wrapper"> All of the edges on the helmet mesh are set to be shaded in a softened fashion. The wireframe mesh updates to display as dashed lines indicating that all of the edges are set to be soft shaded. You may not notice any immediate effect on the smoothed high resolution version, but its important that you perform this step before you proceed to harden specific edges on this model. <span class="anchor_wrapper"> <span class="anchor_wrapper"> <span class="anchor_wrapper"> Tip <span class="anchor_wrapper"> You can quickly select the inner edges surrounding the perimeter of the face shield using the Select Edge Loop Tool. You may need to double-click in a couple of areas to complete the selection. > <span class="anchor_wrapper"> <span class="anchor_wrapper"> Notice that the same edges on the smoothed high resolution version of the helmet are unchanged. For edges to display sharp on the smoothed version, you must turn on the Keep Hard Edge attribute. <span class="anchor_wrapper"> <span class="anchor_wrapper"> To turn on the Keep Hard Edge attribute <span class="anchor_wrapper"> <span class="anchor_wrapper"> To crease edges on the mesh > <span class="anchor_wrapper"> <span class="anchor_wrapper"> Note <span class="anchor_wrapper"> You can toggle the creased edge display (thick lines) by selecting Display > Polygons > Crease Edges. <span class="anchor_wrapper"> <span class="anchor_wrapper"> Your model is now complete. Depending on your requirements you can delete the construction history on both the low resolution and high resolution versions. <span class="anchor_wrapper"> Refine any regions on the helmet as required to gain more experience with the tools presented in this lesson. <span class="anchor_wrapper"> If you need to work with either version of the model separately you can ungroup the two meshes by selecting the top node of their hierarchy in the Hypergraph window ( Window > Hypergraph: Hierarchy ) and selecting Edit > Ungroup.
 * 1) Right-click the low resolution mesh, set the selection type to Object Mode, and then select the helmet mesh.
 * 2) Select Display > Polygons > Soft/Hard Edges .<span class="anchor_wrapper"> The wireframe mesh on the helmet updates to display both dashed and solid lines. The dashed lines indicate edges that are set to display as soft shaded. The solid lines indicate edges that are set to display as hard shaded. The reason some of the edges are hard and some are soft relates to the particular settings for some polygon tools.
 * 1) With the low resolution version of the helmet still selected, select Normals > Soften Edge.
 * <span class="anchor_wrapper"> To harden the edges surrounding the face shield**
 * 1) Right-click the low resolution mesh and set the selection mode to Edge.
 * 2) Select the inner edges that surround the perimeter of the face shield (see image below).
 * 1) Select Normals > Harden Edge .<span class="anchor_wrapper"> The selected edges are hardened on the low resolution mesh.
 * 1) In the perspective view, select only the smoothed high resolution version of the helmet mesh.
 * 2) In the Channel Box, in the Inputs section, click the listed proxy to display its attributes.
 * 3) Set the Keep Hard Edge attribute to On .<span class="anchor_wrapper"> The sharper transition between the face shield and the rest of the helmet now appears on the smoothed high resolution version.
 * 4) Select all of the edges for the grill vents and harden them as well. <span class="anchor_wrapper">
 * 1) Select the lower outer edges on the face shield (see image). <span class="anchor_wrapper">
 * 1) Select Edit Mesh > Crease Tool.
 * 2) In the scene view, press the middle mouse button then drag the mouse to the right to add a crease to the selected edges.<span class="anchor_wrapper"> A thick line appears on the low resolution model to indicate that a crease has been applied.
 * 1) Save your work.