Light included in the AO calculation

[Yannick]

Hi,
I have something that I did not expect when doing a AO pass with the render element (extra texture).
My area lights in the scene create occlusion on my geometry, like they are geometry.
This is not a big problem as I will use render layer instead but the result got me confuse for a moment.

I am using:
V-Ray for Maya version 2.00.04 from Jul 4 2011, 16:16:51
V-Ray: V-Ray core version is 2.00.01
on win 7 64bits.

Yannick

[michae]

I wanna add that lights also show up in the coverage pass. Ive only seen that with the rect light .

[braveRabbit]

I can confirm that. I currently have the same problem and I need to somehow eliminate that. I can probably get away with drawing a matte in compositing but I guess that's not the intended way. (who likes to rotoscope rendered cgi images?)

Here's a little screenshot:


Thanks, Ingo

[vlado]

If the lights are "invisible" it should be enough to turn on the "work with transparency" option for the VRayDirt texture.

Best regards,
Vlado

[Yannick]

Damn, you have an answer for everything...

Thanks.

[braveRabbit]

If the lights are "invisible" it should be enough to turn on the "work with transparency" option for the VRayDirt texture.

Thanks for the answer vlado. This makes sense and I will take a note for that.

Best, Ingo

[michae]

Will the rectangle light in the coverage pass be fixed in future builds?

[vlado]

Will the rectangle light in the coverage pass be fixed in future builds?

Yes.

Best regards,
Vlado

[ricoholmes]

If the lights are "invisible" it should be enough to turn on the "work with transparency" option for the VRayDirt texture.

Best regards,
Vlado

Ah this actually brings up a different problem in a current scene of mine. "Invisible" rectangle lights are visible in refelections (superb!) but not in refractions (disastrous). Is this intentional ? I've been trying to work out if I'm missing something here, or what workaround there might be.

[vlado]

Unfortunately, the camera visibility and refraction visibility are linked together for the moment. It is on the "to do" list to decouple them. If you need it urgently, let me know and we'll see what can be done about it.

Best regards,
Vlado

[ricoholmes]

Ahh superb, thank you.
No immediate hurry. I'm lucky with the current project; a still bottle product shot against a white background. The light only becomes a problem if its intensity mutliplier is brought below 4 (it appears a grey rectangle rather than white at that level vs exposure). Hopefully the client won't require the backlight any less bright.

I can see it being a problem for later shots/brands (against black bg or animations) but for now I'm safe.

[ricoholmes]

Unfortunately, the camera visibility and refraction visibility are linked together for the moment. It is on the "to do" list to decouple them. If you need it urgently, let me know and we'll see what can be done about it.

Best regards,
Vlado

Oh dear, this one has really come back to bite me on the arse now. I was in no rush in July, but just got a major new client (big beer brand.. mmm! beer!) and they have some pretty specific lighting requirements and there's a lot of back-lighting glassworks.

Is there any chance refraction/visibility linking will happen any time soon ? (just crossing fingers now and hoping)

[vlado]

I will try to push this forward a bit. A work-around might be to make the light generally invisible and put a plane with a self-illuminated material in front of it that is invisible in refractions and doesn't cast shadows.

Best regards,
Vlado

[ricoholmes]

Sorry to say, but this one's raising its ugly head again.. the workaround was fine for static shots, but starting to become very problematic for animations. I can really see it being a problem with Phoenix fluid anims as well in the near future

[vlado]

Why would it not work for animations?

Best regards,
Vlado