Hidden objects updated in the viewports?

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Question

When an object's visibility is turned off, it will still update in the Animation Editor (AE), the Render Tree, etc. Is the hidden object still being updated in the viewports as well?

For example, If a heavy object is hidden and you are working on a second object, will you still experience a slow-down in performance when the scen updates, because of the hidden (heavy) object?

Suppose the hidden model contains shape animation, when changing frames is it updated in the viewports? Would there be a performance slow-down due to the updating within the AE, the viewports other areas?

Besides exporting the heavy hidden object out of the scene, is there any other way of improving performance?



Answer

Normally, if an object is not being drawn, it will not be evaluated. Everything in SOFTIMAGE|XSI is pull-based, meaning that the software pulls the data it needs when it needs it. Usually SOFTIMAGE|XSI only needs an object's data to draw the object, or to render it. So, objects that are not visible, it will not be pulled.

Keep in mind that dependencies can affect the number of objects that are evaluated. If, for example, you constrain a simple object to the surface of a complex, shape-deformed, hidden object, the complex hidden object needs to be evaluated (i.e. pulled)so the simple object constrained to it can be drawn correctly. So the complex object is pulled despite the fact that it's hidden.

Hiding objects is a good way to work with large scenes. Some of the user preferences, like optimize interaction or view frustum culling can also help. For example, when view frustum culling is enabled, objects that are not in the view are, in effect, hidden. To see how much it helps, enable it in a very heavy scene.  First orbit/interact with the whole scene in view, and then orbit/interact after framing one small part of the scene.



Applies To: XSI 1.5 on NT,Win2K,Irix

Posted: 5/17/2001


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