Flickering when using vraydirt as a mask

V-Ray V-Ray for 3ds Max Issues
1

Hi,

I have a strange behaviour on my scenen using vraydirt as a mask for a vrayblend material for a stone texture ( lighter material on the outer edges, darker on inner edges ).
As soon as i introduce a camera movement, i get a flickering on the diffuse area of my stone object.
It only appears when i use the vraydirt map in the mask slot of the vrayblend material. I have installed the latest 3.50.04 on 3dsmax 2016, rendering with BF&LC.
i have already send this to support, who told me problem should be fixed in the next update, but i`m curious if someone else has this problem and knows another
workaround then baking the dirt map, which doesn`t give me the same exact result then using the dirtmap.
Maybe someone from chaosgroup can also tell me, when to expect the next update with a fix for this.

thanks in advance

Robin Arnecke

2

I’ve just checked the entire communication and the scene and would like to clarify a few things.
Neither in the communication it is mentioned that he issue will be fixed in the next update.
The issue is not yet addressed by our developers and at this point we cannot specify when exactly it will be fixed.

Regarding the scene, I noticed that all VRayDirt nodes use negative distribution, this makes the DirtMap very sensitive even for small changes of the camera angle which is the main reason for the flickering.
Default value of 1 for the distribution generate flicker free result but it looks like the current implementation of the VRayDirt map is not very well optimized for rendering animations with negative distribution values.

So the second solution would be to tweak the shader to use positive values for the distribution parameter, this of course will change the final look of the shader but you may try to tweak other maps in order to get similar result.

3

Hi Svetlozar,

Kristin from the support team replied to my request in March as follows: “We consider that this is a bug in the dirt map and our team is working in order to fix it.”
This sounded to me like this is going to be fixed in one of the next updates as usually done with bugs in the software.
Anyway…interesting to hear, that this has something to do with the negative distribution value, so i will try to tweak this parameter to see if the flickering disappears.

Thanks

Robin

4

Hi Svetlozar,
i changed the distribution setting to positive values but still get this sort of flickering when using the vraydirt map as a mask in a blend material.
When i turn the mask off, flickering is gone. You have any other advice on this problem ?

Thanks

Robin

settings_vraydirt.jpg
settings_vraydirt.jpg336×514 100 KB

5

Not all the bugs are fixed in the next update, of course we’ll do our best to fix everything but we can’t guarantee that this is going to happen.

Nothing comes to my mind now but I’ll try to play around with the scene and see if there is another way to render it without flickering.

6

I take it this was never addressed since I’ve had it happen in two different situations very recently. In my case it was vraydirt used as a multiply over other textures in a composite map to get some edge darkening. i could provide scene if it would be helpful. Using the latest version of Vray Next.