Culling Options

There are three methods of culling objects in JetStream: backface, by area, and by near or far plane. All of these options are configurable using the Culling options tab.

Backface culling only draws the front face of every polygon in JetStream, which is clearly faster. Sometimes, however, the conversion process mixes up the front and back face of polygons and so you have to tell JetStream to draw both sides in order to not see right through some objects.

Area culling options allow you to set the size of objects within a model that will not be displayed. For example, if you were to set the value to 100 pixels any object within the model that would be drawn less than 10x10 pixels in size will not be displayed.

Culling options by near and far plane allows some degree of control over the resolution of the axis perpendicular to the screen. JetStream uses the near and far clip plane to maximize the resolution of the model on screen. The near and far clip plane boxes dictate constraints for the near and far culling planes.

Setting culling options

1. Go to Tools, File Options, Culling

   The Culling dialog is displayed

   

2. Check the Area, Enable check box to enable the definition of the screen area (in pixels) below which objects are culled and type in the number of pixels in the text box.

3. In the Near Clip Plane area, check the Automatically generated check box to tell JetStream to constrain the near plane to give the best view of the model it possibly can. Alternatively, uncheck this box to manually constrain the near clip plane. JetStream will put the near clip plane no further than the value you type into the Furthest distance text box.

4. Similarly, in the Far Clip Plane area, check the Automatically generated check box to tell JetStream to constrain the far plane to give the best view of the model it possibly can. Alternatively, uncheck this box to manually constrain the far clip plane. JetStream will put the far clip plane no closer than the value you type into the Closest distance text box.

5. From the Backface drop-down, select On to enable backface culling of all objects. Select Solid to cull the backface of solid objects only. This is the default option and that which you are most likely to require. If you find that parts of items are missing in the JetStream scene, you might want to disable this option, by selecting Off

6. Click OK to set these options or Cancel to exit the dialog without setting them.