CGTalk - HDRI & Reflections/Photorealism problem

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LOTK

11-11-2004, 01:05 AM

Hi everyone,

I really encounter a serious problem on making my work realistic and with nice reflections. Worked on brazil for a long time up to now, I can easily work hdr reflections on spheres but not on complex models...

As a reference work I would like u to have a look on the post:

http://www.cgtalk.com/showthread.php?t=164894

I am trying to make something similar but the reflections of my HDR image (known snow field probe) are comming up like in v12-hdr-wrong.jpg. The second image is a render worked out with plains mapped as buildings (no hdr).
My HDR setup is according to Brazil tutorials and also references from another 100 tutorials out there. The material on the paint is brazil advanced.

Just so you know, there is nothing wrong with the model, i've spent about 3 weeks of total work on it.

If you need more information on my setup don't hesitate to ask!

Thanks

cgJD

11-26-2004, 02:01 PM

1) What type of projection are you using for the HDR map? I havent used brazil (as i'm a XSI / mental ray user) but I would imagine that it would either want a Light Probe (Angular Map) or a Lat / Long format - depending what brazil wants.

2) Have you tried another HDR image to see if the effect is the same? It looks as though the HDR image doesn't have a high enough dynamic range.

How much reflection have you got on the vehicle - to get the bright reflections the HDR map needs to have a very high dynamic range (check the values in HDRShop) and the reflection needs to be quite low (about 0.1) this way anything with a normal brightness doesn't get reflected much at all but the very bright highlights (becuase they will have a brightness 10's or 100's times of areas with normal brightness) will appear bright in the reflection.

Another tip is to render out at a high dynamic range (not sure what formats Max / Brazil) supports and take the image into a compositing package (Combustion / Shake) and play around with some subtle glow effects on the bright portions of the image (anything above 1.0). This can add atomsphere to the image.

I Like the model but is it the angle or is the front windscreen a bit small.

Good luck

irwit

11-27-2004, 08:03 PM

id agree totally. Your reflection map is outdoors for one. If your not putting the car in a background or even if you are you could make alot more stylish reflections using a " home made " reflection map " Even if its nota hdr image maping a normal image map with high contrast shapes would produce more of a reflection look that your going for. Theres a also a tutorial out there somewhere, that shows youi how to place reflections on the object so you can get that white streak across the side of the car or wherever you want it really.

Good luck, would like to see how you get on

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