There are several ways to set up symmetrical modeling for polygon meshes in XSI . Some of the older techniques involve scaling by -1, and don't make the best use of some of the newer features available.
Here is a symmetrical modeling setup that is quick to create and easy to use:
- Create the basic half-object that you will be working with, for example, half a cube or half a sphere. If necessary, you can use Modify > Poly. Mesh > Slice Polygons to cut an existing object in two.
- Clone the half-object using Edit > Duplicate/Instantiate > Clone Single.
- Symmetrize the clone using Modify > Poly. Mesh > Symmetrize Polygons. If you don't activate the Bridge option, you don't need to worry about border points lying exactly on the plane of symmetry; they will be merged to their average position.
- Make the symmetrized clone unselectable by editing its Visibility property, or by adding it to an unselectable group or layer. This prevents you from accidentally selecting it in a geometry view, but you can still select it in an explorer or schematic.
- Select the half-object and choose Get > Property > Display. Set the Selected: Static mode to Wireframe, then click Copy Static Selected Mode to All.
- Make sure the viewports don't override the half-object's Display settings. To do this for an individual viewport, click the Display Mode menu at the upper right and uncheck Override Object Properties. To do this for all viewports, choose Display > Display Options (All Cameras), then click the Display Mode tab, and activate Mixed Viewing Mode. Now you can switch to, for example, Shaded mode, and the polygons of the half-object and the symmetrized clone won't overlap.
Now you can do all your modeling on the half object, and the symmetrized clone will update automatically.