CGTalk - Xsi Bump Mapping

Apoclypse

08-25-2003, 05:42 PM

I have a question in regards to the speed of XSI's bumps. I don't really know if this is a mental ray problem or just that shaders that are included with XSI. I find that XSI's bump mapping is damn slow. I have been using the exp version so I thought maybe it was just that but i switched to version 2 and still find the bump mapping to be slow. Is this a mental ray problem ( i can't really tell i still haven't used MR for maya yet) or is this an XSI problem.

The reason I ask is because bump mapping should be one of the fastest things ( even maya's own renderer pumps these out with relative speed and quality).

okno

08-25-2003, 09:18 PM

I have the same problem (in Cinema4D was it OK).
If i aply bump map it dramaticly turn down speed of render time :-(

Atyss

08-26-2003, 05:22 PM

How do you use bump map? Yes, it is slower here too, but certainly not "dramatically".

Cheers
Bernard

Apoclypse

08-27-2003, 05:46 PM

well for one thing it doesn't render as fast as other apps like max or even maya. I have no idea why it is slower. After all this is almost basic in a renderer, and as far as i have seen it should be a fast process.

As for the usage it shouldn't matter but i just basically put a grid map on to the diffuse channel of a pong shader and turn on bump mapping in the grids property editor. It's just slow in compaarison to the same operation in maya or in max ( or LW). My question is if this is MR specific or are the shaders in XSI themselves written this way.

To prove my point go to the xsi net local library thing and open up the rusted metal scene. render that and you will see quite a bit of slowness. ( though in retrospect it does have quite a bit of bump maps in it) but even with just one procedural with bump mapping turned on it still slow.

Atyss

08-27-2003, 06:02 PM

You should avoid using the bumpmap features in some shaders, and avoid plugging anything in the bump input of some surface shaders.

Instead, use the bumpmap_generator and plug it straight to the Bumpmap input of the material node.

Have a look at this:
http://www.xsibase.com/forum/index.php?board=6;action=display;threadid=1023

Cheers
Bernard

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