HDRI render question

# 1 04-03-2007 , 07:14 PM

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hi,

I've got a scene set up with an hdri dome. I've checked the emit light box under the image based lighting tab, so my hdr image is my lightsource. The scene is not very eavy poly wise, but there are a lo of high res textures. About ten or twelve 2048x2048 tga's at 24bit. Also the hdr file is quite heavy, about 18meg.
I am rendering in MR and Final gather. I left all of it at the standard settings except the min and max radius which I adjusted according to my scene.
The rendering times I have are a bit too high, it's about 20 min per frame in 1280x720. As I will have to render about 1000 frames you can probably see my problem. I was wondering if the texture resolution has a big impact on render time, same with the hdr image?
Also is it possible that maya writes a cache file?

thanks

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# 2 04-03-2007 , 07:34 PM

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For the amount of texture info you are using at those res, then 20 mins is more that acceptable.

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# 3 04-03-2007 , 07:50 PM

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ok, thanks

that means, if I reduce my texture size to say 1024 it would cut render time. Would it also make a difference using jpg's instead of tga's?

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# 4 04-03-2007 , 08:04 PM

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I dont think you will notice much of a difference between tga and jpg. its the content of the image. Yes if you drop to 1024 then times will drop

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# 5 05-03-2007 , 03:51 AM

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thanks so much:attn:

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# 6 05-03-2007 , 09:01 AM

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try lowering your samples until you get something that isn't acceptable for what you want. Then start to raise the samples until you get to where you want to be (a nice balance between quality and speed). That way you don't have to resize all your maps down (which will give you blurry textures etc)

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# 7 05-03-2007 , 09:36 AM

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thanks for all your help guys,

@alan
my max sample level is 1 and the min -1. I don't even now wether this is high or low. (sorry for my incompetence, but I am just figuring out that rendering is a science on it's own)

I've achieved a mildly satisfying render time. Mainly by taking most of my textures down to 1048 or 512. I don't plan any extreme closeups anyway. And not using final gather but global illumination instead. It renders nearly twice as fast with acceptable results.
The image below was rendered in 12mins, still a bit too long, but I will replace the textures of the background buildings with 128's. And play with alan's suggestion.

cheers

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