Performing a Symmetry

You can create a symmetrical subdivision surface with or without intersection. There are two types of symmetry:

• no intersection between the subdivision surface and the symmetry plane
• intersection between the subdivision surface and the symmetry plane.

1. Click Symmetry .

   A Tools Palette is displayed:

   
   
   

   The following icons inform you about the input selection:

   
   
   • surface
   • plane

2. Select a surface.

   Plane Selection becomes active.

3. Select the plane.

   You can also select the plane first then the surface. In this case, Surface Selection becomes active.

   
   
   • Without intersection:

   
   
   

   The result is the mathematical symmetry by a plane:

   
   
   
   
   • With an intersection:

   The surface is made of two parts separated by the plane. A side of the surface is automatically chosen, corresponding to the bigger side:

   
   
   

   A new Side Selection icon appears in the Tools Palette to let you choose the side.

4. Click it or click in the 3D area to invert the side of the symmetry:

   
   
   

5. Click to add weight to the intersection of symmetry. You can also access this command by pressing ALT+SHIFT+H.

   A click on the attraction type icon modifies its state. The icon has two states,

   
   

   • to give a sharp edge:

     
     
     

   • to give a smooth edge:

     
     
     

   The value of the weight, displayed on the right of the screen can be changed between 0 and 100:

   
   
   

6. Hold the left mouse button and move the mouse to reach the desired value on the weight slider.

7. Release the left mouse button when you are satisfied with the weight added to the surface.

   Important: To create a sharp edge at the symmetry plane, the subdivision surface must intersect the plane and a sharp edge must already exist.

Selecting n number of subdivision surfaces will create n number of subdivision symmetries.

You can concert a subdivision symmetry into a subdision surface. Here is an example of a specification tree when a symmetry is created:

1. To convert a symmetry feature into a subdivision surface, right-click the symmetry in specification tree (here Subdivision Symmetry.1) or geometry and select IMA-Convert Into Subdivision.

   A new subdivision is created.

   Tip: You can also access this command by pressing ALT+SHIFT+C.

2. Select the Convert Into Subdivision command on Subdivision Symmetry.1. A new subdivision surface (Subdivision Surface.3) is created:

   
   
   

   Tips: All the graphic properties and the material of the symmetry are kept for the new subdivision surface. The Convert Into Subdivision command works for multiple selection also.

You can copy and paste a subdivision surface that is a symmetry.