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giantrobot
04-13-2003, 07:26 AM
Hi-

If you are a skilled Brazil user, can you give me some tips?

I have a WIP that was using the scanline renderer and max's native HDRI. The image took 1 hour to render at 640x480 with no depth of field. I switched to Brazil (beta) and my render was now 6 minutes!

ok, but it took a while and a good brazil/hdri tutorial to get me in the same ballpark with the render (because i actually liked the scanline...just took too long).

please look at the image below, notice the listed differences and perhaps let me know how to get the brazil render more similar to the scanline. the top is scanline, the middle is brazil with the skylight at .8 brightness and the bottom is brazil with the skylight at .65. the only difference between the 2 projects is that the brazil one uses a smaller blurred version of the HDRI for the brazil skylight:

-why are the eyes so dark in the brazil image? (my eyes are the typical 2 layers. one for the white and iris, one for the gloss and lens. both are max raytrace materials, blinn)
-when i get the light right to match the nose , it is too dark on the cheek.
-in the scanline, the helmet's white areas seem more reflective (ie. near chrome rivet) and less blown out (nice blues, etc).
- the chinstrap does not look reflective at all in the brazil render

http://www.ryanlesser.com/images/webviewing/brazilvsscanline.jpg

Thanks in advance!!!
ZeBoxx
04-13-2003, 08:56 AM
Hello,

I think the basic issues at hand here are :

1) Using RayTrace Materials
RayTrace materials cast fully opaque shadows with Brazil r/s - it's quite possible that under the scanline renderer, they do not.
The Brazil r/s Test Material has an option for "Transparent Shadows" in the RayTrace Controls rollout - it would probably give the correct result.

RayTrace materials also do not reflect/refract global illumination.
The strap over the chin not reflecting as much ? It's reflecting as much - but as far as the Raytrace material is concerned, the chest is not being lit by skylight. So the reflection is likely there, but dark.

2) Using only skylight.
You might also want to use Indirect Illumination to bounce the light around a bit more. I'm not sure how much the scanline renderer used.

One more thing to note - is that the exact same Environment background setup ?

If so - I have no clue why they look so much different. The Brazil r/s one looks correct enough, though.


Anyway - in short.. try replacing all the RayTrace materials (and materials with RayTrace maps) with Brazil r/s Test Material equivalents.
giantrobot
04-13-2003, 01:04 PM
I am currently rendering the scene with the changes you suggested. the 1st bucket is the eye and it looks good so I am guessing everything is cool now. Thanks so much.

PS: is there any place out there that renders things for folks at higher res than the beta allows? All I can get is 1024x768, but I am going to try to submit this piece when done to the cgtalk Expose book competition and they need much higher rez. Also, depth of field is crashing my brazil/max, so i need someone with the full brazil for that too :(

let me know.

THANKS AGAIN!
ZeBoxx
04-13-2003, 01:31 PM
Heya,

For the resolution limit - you're free to construct a series of cameras (smaller FOV's skewed to position), render those out, and stitch the result together.

(can't recall if blow-up works in the pubtest.. don't think it did - if it does, use that)

For the DoF part.. I think you may just be going too high on settings.

I don't know of any particular 'service' for high-res renders for pubtest users, but you can always ask one of the betatest or support guys. I'd suggest dropping by on the chat (some 6-8 hours from this writing is when most people are around) and asking around.

Don't ask me, though - limited resources (machine and software-wise) :/

Best regards,
Richard Annema
giantrobot
04-13-2003, 02:12 PM
good ideas.

wouldnt the multi cameras mess up the perspective or something when trying to stitch? i think that blow up actually does work...ill give that a shot :)

as far as dof, if the settings are lower, i get tons of noise in the image. noise that is not there during non-dof renders. i bump up the settings and do a region test render and it looks good...it just will not render the full image without crashing.

i have an AMD dual 2000+ with a gig of ECC ram.
drewbie
04-13-2003, 09:04 PM
If you use a skew modifier on the camera, you will not lose the persepctive, and you can then render out the sections that you need.
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