hdri reflections - fg illumination versus reflection

[anthonymcgrath]

-heres a piccy of the car so far. I'm using final gathering for illumination mapped to a hemisphere nurb ball surrounding the scene with primary rays turned off. The cars reflectivity is quite high (rangin from 0.2 to 0.6 I think) so its reflecting the nurbsphere.

-Its strange but when I added a reflection map and tried to light it using normal lights (method 1) the reflections seemed to appear 'stenciled' on - the blacks of the .hdr map were quite pronounced and seemed textured on. This 2nd method seems to yield much nicer results and seems right but its just a bit confusing really.

ps - sorry if the black areas seem quite dark (looked oreet on me monitor last night!) :D

-also used the cameras depth of field pass (using that cool DofControl mel script) to get some subtle focus shift. That took bloody ages to render tho - is there no quicker way of getting the same dof effect with mr thats a bit quicker? I found a mr lens effect but it seemed to completely blur out the camera. :shrug:

-lastly, can anyone tell me why the reflections seem quite 'warped' on the corner of the bumper (below the light). They seem to converge to one point.

cheers
ant
newc
uk

http://www.photobucket.com/albums/v90/anthonymcgrath/car_inprogress08.jpg

[pappuftp]

the pinching u are refering to could be the texture that pinches at the polar points of the sphere u are using to hold the reflection map..

[Splin]

hey anthonymcgrath
Can you describe your process a little bit closer. I am particulary interetsed of being able to have black background and light the scene myself, like you did it. It is no problem to set up nice fg scene with nice reflections. In Maya 6 there is ibl or if in older version you could make simple spehre and map ur hdr to there. But with that technique I seem not to be able to figure out how to do it. You mentioned that you turned off show primary rays, where?
Thx ;)

[anthonymcgrath]

My process involves the older method of mapping a nurbsphere with me hdr map (now got it saved as a mel button :D as I'm bone idle!) as opposed to this newer ibl method that I've heard mentioned (dunno what that is tho). The hdr sphere is simply left as is and I amend the specular colour of the cars shader to intensify highlights and wotnot taking the value above 1 to 2 or 2.4 which seemed to work out quite nicely. I'll try n put the scene up when I get a minute with some comparisons on the other method (mapping the cars reflectivity).

[Splin]

Cool man. The new ibl is nothing more than just making it much easier to setup those hdri lighting domes. It automatically makes virtually infinite large sphere, very easy to apply texture on to it. But whatever I do I can not black out that dome so that I would not see it on rendering, like you have it on your pic. Still see reflections and light with it in a subtle way but keep the dome black. Tho I have few ideas what need to be tested out. That scene would be very cool if you could share it ;)

[anthonymcgrath]

Well I wouldn't know how to hide the bg dome with the ibl but I do know that if your using the nurbsphere method like me you can simply select the sphere, goto its render stats then turn off primary rays causing it to just light the scene, cast reflections but not actually render.
hope this helps. The reflections on my car are controlled by a ramp plugged into the reflectivity of the car shader. This is then controlled by the sampler info node and a bit of tweaking.

to be honest theres a heap of bods on this site doing car shading and lighting a heapload better than mine. My post is simply to try n get some thoughts on which method people prefer in order to obtain reflections. Unfortunately no-one else has posted really.

I'll post up the scene tonight (cant post up the full car model unfortunately but can stick a proxy in there to give you the idea).

[Splin]

Ok now I get your idea, ahah. Thats where this hide primary visibility is hidden. Thx man, I'll try it out.
Well yes, everyone seems to know but noone participates :hmm:

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