Microsoft KB Archive/159023

= Microsoft Knowledge Base =

PRB: Camera Controls Produce the Appearance of Object Jaggedness
Last reviewed: November 27, 1996

Article ID: Q159023

The information in this article applies to:


 * Softimage 3D for IRIX, versions 2.66, 3.0, 3.5, 3.51
 * Softimage 3D for Windows NT, versions 3.0, 3.01, 3.51

SUMMARY
When you zoom in on an object, you notice jagged edges on the texture maps.

CAUSE
When you launch Softimage 3D, the default angle for the camera's field of view is about 41 degrees (located in Camera->Settings in the Custom Angle field). When you zoom into your model, the position of the camera does not change, but the lens' Custom Angle (or "field of view") gets smaller. Pressing the 'a' Supra key does not change this angle value, but positions the camera just far enough from the model that it fits within the field of view angle and occupies a "frame all" area in the perspective view. When the angle of view is too small, errors in the texture display appear.

Resolution
This procedure will help you understand how certain camera controls affect your scene.

 Choose Get->Primitive->Cube. From the Matter module, choose Texture->2D Global, and select XY coordinates as the Mapping Method. In the Shade view setup, enable Hardware Texture. You now see the textured model in the view. Orbit the camera, using the 'o' Supra key, so that you see the front face and the right face of the cube in the perspective view. Press the 'z' Supra key (zoom) and the middle mouse button to zoom in. Press the 'a' Supra key to frame the model in the view. If you have zoomed enough, you will notice jagged edges on the texture maps.  Choose Camera->Reset, then orbit the camera again using the 'o' Supra key. The jaggedness disappears. This command resets all camera parameters to their default values. To prevent errors in the texture display, use the Camera Dolly feature ('p' Supra key) to dolly the camera towards your model. When you use this function, the field of view value does not change, but repositions the camera. 