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EXR Displacements Under Exposed

14 REPLIES 14
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Message 1 of 15
FalconCrest
545 Views, 14 Replies

EXR Displacements Under Exposed

I want to know why, when exporting a multi-tile displacement map from Mudbox, one of the tile displacement EXR is extremely under-exposed, compared to the other tile, of the two tiles I exported ?

 

I ran the OpenEXR EXRDisplay utility in hopes I could fix the exposure, but the utility failed, even after adjusting the exposure in within the tool, it did not increase the exposure. 

14 REPLIES 14
Message 2 of 15

are baking 16bit EXRs..?

have you tested them with sculpt mesh with map in mud..?

normalize to search distance turned off.?

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https://linktr.ee/cg_oglu
Message 3 of 15

32bit displacement maps, and Normalize to Search distance is disabled. Scuplt using displacement map works but because it is part of a multi-tile displacement both displacement maps, when using sculpt using displacement maps both images for the two tiles look identical, that doesn't tell me why one of the displacement images is under-exposed.
Message 4 of 15
3dMastermind
in reply to: FalconCrest

Check the normals. It think if they are longer in one region then the maps will differ even if the geo looks the same.

 

Also, please let us know how to reproduce this issue.

 

 

 

 

 


Manny Papamanos
StingRay | MotionBuilder | Maya | Mudbox
Games QA Specialist



Message 5 of 15
FalconCrest
in reply to: 3dMastermind

Sorry, what do you mean if the normals are longer in one region ?

Reproduction of the Issue is as follows;

1. Create a mesh in Maya
2. Import the Mesh into Mudbox, do some adjustments to the mesh.
3. Import the mesh into Maya or 3rd party UV creation program, create clean UV. If this is done in Maya, create as mentioned, clean UV's, in this case consisting of up to (2) UV tiles, move one UV shell to the second tile on the right (1-2 uv), the first tile being obviously (0-1 uv).
4. Import UV, or the mesh can already have UV's, which ever route you prefer to take, as long as there are two or more tiles, I know I said (2) tiles, and a UV shell is placed in each of the tiles, up to the max of (4) tiles.
5. Export the displacement maps to 32-bit EXR, if the issue repeats its self as in my case, the first tile which is in the (0-1 uv) space should not be under-exposed, while the second tile, maybe the third tile, will be under-exposed.

Photoshop levels can aid in visualization of the exposure !
Message 6 of 15
3dMastermind
in reply to: FalconCrest

In my case, the color/exposure of the map on the UV that is in the 0-1 space is the same as the UV islands that are out.

Can you send a sample Maya scene with it's UVs to the case you logged with us.

I'll be glad to test that in Mudbox.

 


Manny Papamanos
StingRay | MotionBuilder | Maya | Mudbox
Games QA Specialist



Message 7 of 15
FalconCrest
in reply to: 3dMastermind

I can send the scene. Tile 1_2 when viewed in Photoshop levels is under exposed,  Tile 0_1 could be better but it's not as extreme as Tile 1_2. 

Message 8 of 15

could you import the dispmaps as diffuse layer in mudbox and show us some images...

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Message 9 of 15

I had to exaggerated the color in Mudbox otherwise you would see nothing.

 

Tile 1

 

 

Tile 2

 

 

Message 10 of 15

looks strange yes...

 

but if you say sulpt using disp is working fine... than it should be fine...

if the naming conventions are right... like texturename_u1_v1 and texturename_u2_v1

mudbox will read both uv tiles...

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https://linktr.ee/cg_oglu
Message 11 of 15

Sculpt using displacement map on a grid works, the results are far from great.
Message 12 of 15
3dMastermind
in reply to: FalconCrest

Hi.

these are my tests with your scene, previewed with the Softimage flipbook [my preferred viewer]

 

The 32bit ones are consistent, but they are both darker and the details seem to be on the red channel.

 

As for the darker .32bit with details in red...

I don't know if this is a previewing issue (also nothing logged on the issue),

it's possible that the 32bit data would get picked up corrrectly from the displacement inside the renderer.

 

These are 16bit .exr(FP):

 

exr1_16bit.JPG

 

exr2_16bit.JPG

 

 

These are 32 bit.exr(FP)

1_32.JPG

2_32.JPG


Manny Papamanos
StingRay | MotionBuilder | Maya | Mudbox
Games QA Specialist



Message 13 of 15
FalconCrest
in reply to: 3dMastermind

The images are similar to what I posted previously. The key is to open the images in Photoshop and view the levels, that is where you will see the under-exposure.
Message 14 of 15
3dMastermind
in reply to: FalconCrest

Hi.

 

The question here is that when the displacement is applied inside a 3D program [that can properly parse the 32bit.exr],

does that yield bad results?

From my understanding, 32bit images contain data that we can't necessarily preview with a typical viewer because it contains a range of data larger than a monitor can display.

 

From docs:

"A 32 bit image, also referred to as a high dynamic range image (HDRI), records all of the positive and negative distance values beyond the 0 to 1 range, so it contains much more information than can be displayed on your computer monitor. To view this full range of values you need a utility that displays HDRI images such as the Image Browser in Mudbox."

 

Also, I don't use this software: "Photoshop".

For me, when viewing with the Mudbox "image browser" all seems good.

 

If you still feel like it's a defect.

I will have to log the issue so that QA/Dev can take a closer look.

 

Thanks for reporting,

 

and let us know.

 

 

 

 


Manny Papamanos
StingRay | MotionBuilder | Maya | Mudbox
Games QA Specialist



Message 15 of 15
FalconCrest
in reply to: 3dMastermind

I started the thread wondering why one UV tile was under-exposure over the other UV tile. I didn't think there was any defect with Mud, as well as I know that EXR contain number data over color values.

I was only curious to the under-exposure values that can be read by Photoshop, regardless what utility you prefer and I know there are utilities that can display EXR better then Photoshop, other then maybe if you have an extremely high resolution monitor that can display HDR.

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