matte slowdown

[Gijs]

When assigning my floorplane a vray mat with vray wrapper, matte, alpha -1, affect shadow and alpha checked, the rendering slows down tremendously for 5minutes to about (estimated time) 1 and a half hour. What's going wrong here?

[panthon]

Why don´t u just check this settings in the vrayproperties? Do you need the wraper for any particular reason?

[Da_elf]

is there a speed difference?

[Gijs]

I tried both, but there does not seem to be a difference

[Da_elf]

didnt think so

[panthon]

I tried both, but there does not seem to be a difference

that´s bad news

[Gijs]

can someone please test, just a simple plane and a simple teapot and a vray light above it, lightcache for first and secondary bounces, and plane vray-properties:
matte
alpha: -1
affect alpha and shadows checked

rendertime is enormeous

when GI is off, bucket rendering is fast as expected...

[Gijs]

O.K.,

just ran another test with irradiance/qmc, then it is fast again,

so it looks so far a lightcache related problem.

[vlado]

The light cache does not store information for recovering GI on matte objects and in that case, QMC GI is used for the matte material. The irradiance map, on the other hand, stores matte GI information, so this is not a problem.

Best regards,
Vlado

[Gijs]

Ah, O.K., that is what I thought. Will this be in newer builds of Vray, or is technically too complex for the time being?

[Erik N]

So, this means do not use Light cache for secondary when rendering matte objects?

[vlado]

Ah, O.K., that is what I thought. Will this be in newer builds of Vray, or is technically too complex for the time being?

It's not easy to do this, due to the nature of the light cache, so I don't think this will be implemented.

Best regards,
Vlado

[vlado]

So, this means do not use Light cache for secondary when rendering matte objects?

You can use it safely for secondary bounces, but not for primary bounces; for primary bounces it will be faster to use the irradiance map with matte objects.

Best regards,
Vlado