particles - opacity - alpha errors

[JANGLED_NERVES]

Hy again,

as in the thread "particles don´t render opacitymap", the particles now render (with the great help of DaForce).

But now the alpha channel is wrong (see image). Possibly it has something to do with the opacity map and the channels...

any ideas?

[^Lele^]

Try adding some bitmap filtering to the opacity map.
It sure renders faster without, but this looks like the price you have to pay when up-close and personal with it.
Then again, i may be well wrong.

[JANGLED_NERVES]

filtering is already on, whether "pyramidal" nor "summed area" is changing something. DaForce already said, that I should turn filtering of, to render faster. Unfortunately turning of won´t help either.

HELP!!!

[JANGLED_NERVES]

If I make a mesh out of the PF source via Mesher, the errors are gone. So it has something to do with vray and PFlow...I would prefer a version without the mesher...Anybody a solution?

[vlado]

You can try to increase the max. transparent levels in the Global switches rollout of V-Ray and also increase the secondary rays bias slightly.

Best regards,
Vlado

[JANGLED_NERVES]

I already tried this one, no success.

in the

> global switches < rollout, I raised the

> Max transp. levels < to 500 and the

> Secondary rays bias < to 0.01.

It´s changing slightly, but the main problem still exists. Why is Vray handling the particle System in this strange way?

[RErender]

Looks like the edges of the planes? Maybe try turning off tiling for the bitmaps and or turn on bitmap cropping.

[JANGLED_NERVES]

Ok tried this too, no effect. Whether tiling, nor cropping. I think there is something really wrong, I don´t dare to say...maybe a ... bug ... ? Also possible is that the particles, generated via script, thanks to Pietro Salerno, are somehow wrong, but I am not into scripting...

...any other ideas?

[^Lele^]

try and upload a part of the scene, somehow crippled so noone could rip it, and someone'll try.
Chill, brother.

[JANGLED_NERVES]

Hey Lele,

I sent you the file by email...

greetz to italy, d.

[DaForce]

Im thinking its a bug, this is the 2nd time (on this scene) that vray has rendered improperly when dealing with opacity maps within pflow.

Also make sure everything is map channel 1 as well

[^Lele^]

Omni_Darker is a light with multiplier -0.9

Turning that light off renders a perfect alpha channel.

[DaForce]

weird tho how he said it works fine when converted to mesh out of pflow.

[^Lele^]

yep. anything below 0.0 multiplier produces the issue (which in this case is only on one side as the light has a definite range).
I wouldn't know if it's a bug or not

[JANGLED_NERVES]

Ok, Lele, the master,

solved the problem. I had on the left side a light with a negative multiplier and this light produced the errors in the alpha channel. I didn´t know this.
Is Vray always producing these effects with negative lights? Anyway, now I´am able to render the scene.

Thanks to all of you, for the support!!!