TUTORIAL: Faster Displacement by Optimization


Hey guys,

I already posted this over at xsibase, so I figured I’d post it here too.
This is a short videotutorial on setting up displacement (using a publicly available example ZB3 head obj and displacement tiff texture) in XSI so that it renders very very fast and looks great still.

Click image to watch:

(No sound, but it’s easy to follow; just pay attention to the mouse cursor.)

[size=2]This goes out to those who are under the impression that displacement = eternal renders. That shouldn’t be the case. :slight_smile:

I should note that although “View Dependant” is generally a good idea in most cases as it optimizes based on the camera’s distance to the character, if you see artifacts when you get really up-close, just toggle it off and that should fix it. (Of course, it’ll be just a little bit slower… still pretty reasonable rendertimes though.)

Last but not least, if your character needs even more detail, instead of subdividing it more under the Polygon Mesh tab of the Geometry Approximation property, I recommend you just crank up the “Max” attribute under “Subdivision Limit” (Displacement tab)… it’s more efficient this way.

If you already know this stuff, then good for you. :thumbsup: Some people don’t know and I hope this will help them.

Any constructive critiques welcome.

-- Alan



nice of you to share these tips with us Alanf.
thank you !!!


You might get an even faster render if the object was smaller and fit in the grid. Wouldn’t the BSP need to be huge to cover that?


I’m familiar with BSP optimization and I agree it would help, of course, but that’s a whole other topic and I didn’t want to overcomplicate the tutorial. My tut is about optimizing the displacement settings, not the entire render. :slight_smile:


excellent. Thanks for taking the time to put this together!


It has come to my attention that enabling “Sample Displacement before Rendering” under the Optimization tab in your Renderer Options will ocassionally drastically speed up displacement rendering even more.

However, you must understand what it does: when ON, it allows mentalray to “know” the correct bounding boxes for BSP calculations (whereas without it it just samples the original displacement-free mesh.) This, in theory, would make BSP more accurate and ultimately faster in the overall render. It is ON by default.

It’s up to you; give it a shot with and without and make your own conclusions. There may be times when disabling it might be beneficial and there may be others when despite your attempts at further optimizing the other parameters, it still impairs your render and maybe OFF works best for you.

One thing’s for sure though: toggling it will NOT affect your render quality, just overall render times. mmkay? :slight_smile:

Last but not least, while I didn’t cover it in the tutorial because it’s about optimizing displacement, not renders overall, I’d recommend any newcomers to read up on what the BSP is and how you can optimize it for your render cameras.


Great stuff!! Thanks for taking the time to capture the demo.


This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.