only reflections....

[lightpixel]

hello guys,

I am a vray user for six years, but here is a silly problem, theat I can´t solve myself.
I want to render out only the reflections on the floor box, but not himself as you can see in background. I tried several techniques (alpha canal, matte object, vraymaterial wrapper), but I get no good results.... I Think, there is a little trick and hope, that somebody can help me...

thanks a lot.

chris

[3LP]

I don't exactly understand what you want to do, but you can put all your objects to "not visible to cam".
You will have your reflection without all objects.
And if you don't want to shadows on the floor, you put "don't cast shadows".

Hope it help.

Stan

[lightpixel]

no really what I mean...
I have to render the complete scene, but from the bottom box, I only want to see the reflections - the rest of the floorbox should be pure white... do you understand me??

regards
chris

[Stefan K.]

hi,

if i understand you right, you don't want to see the ground box (specially the hard line when it meets the horizont...)at all, only reflections and shadows. if done something like that in the past with a gradient ramp in the opacity map that fades out(maybe also as reflection map). Sure not perfect (long rendertimes for example), but it works in my case! i'm sure there are better ways to do it...

wbr

stefan

ps: i can remember i used a plane not a box for that, there were some problems with the mapping...

[DanielBrew]

Chris,

For a very open scene like the example you've shown, try adding a VRay color map into the environment slot of your floor material. Start with RGB values of 1.2 increase them incrementally and you should be able to get a pure white floor but still be able to see the reflections.

Dan

[lhickey]

it might be very silly thing to say but, have you tried playing with the reflections and specular passes only in comp?

Luigi

[lightpixel]

hy daniel,

thank you for the tip. I give it a try!!
@lhickey: yes, I´ve made many test with vray render elements, but get no good results...
For me, it´s not possible, to render out only the floor reflections in a seperate pass....
btw, I have to render 75 konfigurations (as you can see above) till next thurstday

thanks a lot for your help

regards
chris

[victor.nsy]

75 ... man you are killing yourself.. good money I hope.

[lhickey]

Have you tried the RawReflections pass/element?

It gives you reflections on top of a white background.

I just tried, well the result it's not exactly the same as the one you have in the final render but that's because, I assume, your "ground" it's not pure white.

But at least it's a (raw) solution to your problem.


Luigi

[lightpixel]

hello again....

daniels solution work very fine for me.
I did the mistake using a dome-light with a Hdri-map.
Now the scene is only illuminated by a hdri-map in the vray envirement slots.
no other lights. now it works.

[DanielBrew]

Cool, glad it worked.

I was thnking after I'd posted that maybe you should use a VRay override material, using the 'new' floor material as the base material and your 'old' floor material as the GI, reflection and refraction materials.

Dan