VRayMtl + Bump Slot + Filtering issue !

[stilgarna]

Hello Vlado,

I'm using a very big map in VRayColor2Bump, 10240px square, so I'm using VRAYHDRI + Tiled EXR (very efficient, by the way !!!)

Here is my result :



#1 big issue
#2 less
#3 no more issue

#4 and #5 are render directly into VRayLightMtl and I don't see any filtering issue.


VRay 2.40.03
No GI
Filter Maps for GI is ON
I'm using vray universal settings (the latest one)


The problem seems to came from the bump slot into the VrayMTL and filtering in general. (But I'm not a specialist )

I tried the 3 differents type of filtering into VRayHDRI map and nothing have changed.
I tried to plug a 3Dsmax bitmap into bump slot with the original PNG, that I used for creating tiled EXR, and the problem is close to the VRayHDRI one.


As you can see the filtering is correct, but not in bump slot.


Please help !

Best regards...

[stilgarna]

Sorry for double post !!

[vlado]

That seems odd; can you get me the scene? Also, I'm not sure if we added the bump delta scale parameter to VRayColor2Bump in 2.4, but reducing it might help if it's there.

Best regards,
Vlado

[stilgarna]

That seems odd; can you get me the scene? Also, I'm not sure if we added the bump delta scale parameter to VRayColor2Bump in 2.4, but reducing it might help if it's there.

Best regards,
Vlado

Hello Vlado,

You've got a mail , from fabien at le-truc dot ch (ready for download in 20minutes)



The only parameter in the VRayColor2Bump is height. (2.40.03)

I made a simplest version of this scene, 2 objects, 2 lights (VRayLights 1 dome full with VRayHDRI map, and 1 plane), and only 3 VRayMtl

I try more thinks :

Dome Only: OK
Dome + Plane : Problem

Maybe it is a Spec/Reflection issue, or a size issue, parts are very small (6mm)
Maybe with a particular angle at that size, we've got a problem.

As I say, I'm not a specialist, just a regular user

Best regards.

[stilgarna]

Hello Vlado,

Any clue ?

Best regards...

[vlado]

So this is not a bug; your bump texture is simply not uniform. If you blur the texture a lot you will see that one side is brighter than the other especially near the center, which causes the imaginary bump surface to wobble about, causing the cross-shaped highlights. The effect is always there, but low blur values make it less visible.

Best regards,
Vlado

[vlado]

Also, I didn't notice that you have mapped anisotropy. Setting the anisotropy axis to "map channel" might help too. But it would be good to use a better bump texture.

Best regards,
Vlado

[stilgarna]

So this is not a bug; your bump texture is simply not uniform. If you blur the texture a lot you will see that one side is brighter than the other especially near the center, which causes the imaginary bump surface to wobble about, causing the cross-shaped highlights. The effect is always there, but low blur values make it less visible.

Best regards,
Vlado

Hello Vlado,

I try a new map (more uniform, as you said) and no change...
I try Anisotropy based on map channel, it's worse.

the old one look like this :


the new one is :

[stilgarna]

With this more uniform map, even I lower the blur value I always got this "bug".

Best regards...

[vlado]

Can you send me the new map so that I can put it in the scene and send it to you? Worked fine for me.

Best regards,
Vlado

[stilgarna]

Can you send me the new map so that I can put it in the scene and send it to you? Worked fine for me.

Best regards,
Vlado

I know you are very busy at the moment but do you try the new map ?

Best regards.

[stilgarna]

Any news ?

Best regards...

[svetlozar.draganov]

Hello stilgarna

Vlado is usually very busy and sometimes he just do not have enough time to resolve all the issues.
Would it be possible to send that scene along will all assets to support@chaosgroup.com
Please include a link to this thread into the mail.
Thank you very much in advance.

[tashko.zashev]

Hello stilgarna,

It seems that the main issue is the 3ds Max Bump map filtering.
You can check our reply to your ticket.