OBJ Exporter does not save the interpolation used in a texture #101182

New Issue

Arsen · 2022-09-19T07:39:12+02:00

Arsen commented

2022-09-19 07:39:12 +02:00

System Information
Operating system: Win.10
Graphics card:RTX 3070 TI

Blender Version
Broken: 3.2.1
Worked: N/A

Short description of error
Coloring does not work right after exporting from blender.


This is because the texture used in the UV map loses the `Closest` interpolation.

Exact steps for others to reproduce the error

Download attached .blend file and .png image to the same directory
Export the Object to .obj
Reimport in Blender or any other application

issue thing.blend

**System Information** Operating system: Win.10 Graphics card:RTX 3070 TI **Blender Version** Broken: 3.2.1 Worked: N/A **Short description of error** Coloring does not work right after exporting from blender. |![tree blender.PNG](https://archive.blender.org/developer/F13512143/tree_blender.PNG)|![tree studio.PNG](https://archive.blender.org/developer/F13512142/tree_studio.PNG) | -- | -- | This is because the texture used in the UV map loses the `Closest` interpolation. **Exact steps for others to reproduce the error** - Download attached .blend file and .png image to the same directory - Export the Object to .obj - Reimport in Blender or any other application [issue thing.blend](https://archive.blender.org/developer/F13519147/issue_thing.blend) ![ImphenziaPalette01.png](https://archive.blender.org/developer/F13519148/ImphenziaPalette01.png)

Arsen commented

2022-09-19 07:39:12 +02:00

Added subscriber: @ArsenHere

Germano Cavalcante commented

2022-09-19 21:30:15 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2022-09-19 21:30:15 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Germano Cavalcante commented

2022-09-19 21:30:15 +02:00

Could you provide a simple .blend file that has the problem?

Arsen commented

2022-09-19 22:38:41 +02:00

issue thing.blend

I got the blend file and the texture.

[issue thing.blend](https://archive.blender.org/developer/F13519147/issue_thing.blend) ![ImphenziaPalette01.png](https://archive.blender.org/developer/F13519148/ImphenziaPalette01.png) I got the blend file and the texture.

Arsen commented

2022-09-19 22:39:37 +02:00

do you also need the OBJ file?

Germano Cavalcante changed title from ~~Wierd Coloring. I'm not sure whether this is blender or roblox studio...~~ to OBJ Exporter does not save the interpolation used in a texture

2022-09-20 15:34:18 +02:00

Germano Cavalcante commented

2022-09-20 15:37:33 +02:00

Changed status from 'Needs User Info' to: 'Needs Developer To Reproduce'

Germano Cavalcante commented

2022-09-20 15:37:33 +02:00

Added subscriber: @aras_p

Germano Cavalcante commented

2022-09-20 15:37:33 +02:00

@ArsenHere, what is happening is that the image used to define the object's colors has very low resolution (only a few pixels) and the roblox material is reading this texture with interpolation.

It's like you're changing the interpolation type in Blender's texture node to something other than Closest.

I'm not sure if Wavefront .obj supports different texture interpolation filters. (Could it be these blendu and blendv options?)
https://en.wikipedia.org/wiki/Wavefront_.obj_file#Texture_options

@aras_p, as the obj expert, can you tell if this is something that can be supported?

@ArsenHere, what is happening is that the image used to define the object's colors has very low resolution (only a few pixels) and the roblox material is reading this texture with interpolation. It's like you're changing the interpolation type in Blender's texture node to something other than `Closest`. I'm not sure if `Wavefront .obj` supports different texture interpolation filters. (Could it be these `blendu` and `blendv` options?) https://en.wikipedia.org/wiki/Wavefront_.obj_file#Texture_options @aras_p, as the obj expert, can you tell if this is something that can be supported?

Aras Pranckevicius commented

2022-09-20 16:30:14 +02:00

@mano-wii all I can find is that blendu/blendv control "texture blending", but nothing in the whole internet explains what it means by that lol :) So yeah I've no idea if 1) it's possible to indicate that texture needs to be Point/Nearest sampled in the .obj files, and 2) whether (ab)using blendu/blendv syntax for that would even be understood by any other software.

@mano-wii all I can find is that `blendu/blendv` control "texture blending", but nothing in the whole internet explains what it means by that lol :) So yeah I've no idea if 1) it's possible to indicate that texture needs to be Point/Nearest sampled in the .obj files, and 2) whether (ab)using blendu/blendv syntax for that would even be understood by any other software.

Germano Cavalcante commented

2022-09-20 17:22:39 +02:00

Changed status from 'Needs Developer To Reproduce' to: 'Archived'

Germano Cavalcante closed this issue

2022-09-20 17:22:39 +02:00

Germano Cavalcante commented

2022-09-20 17:22:39 +02:00

It doesn't seem to be supported then.
I'm closing it since it's not really a bug.

It doesn't seem to be supported then. I'm closing it since it's not really a bug.

Arsen commented

2022-09-20 17:34:34 +02:00

oh so what you're saying is that since the resolution is too small, roblox studio uses the blurred version of the image. and that this causes some colors to blend causing the weird hue?

Germano Cavalcante commented

2022-09-20 18:04:37 +02:00

In Blender, the interpolation values for the texture have been set to Closest and this option is not supported in obj files.
See https:*docs.blender.org/manual/en/latest/render/shader_nodes/textures/image.html#properties and https:*en.wikipedia.org/wiki/Texture_filtering for more details about interpolation.

In Blender, the interpolation values for the texture have been set to `Closest` and this option is not supported in obj files. See https:*docs.blender.org/manual/en/latest/render/shader_nodes/textures/image.html#properties and https:*en.wikipedia.org/wiki/Texture_filtering for more details about interpolation.

Arsen commented

2022-09-20 18:39:01 +02:00

ohhhhhhhhhh that makes sense thank you

Bastien Montagne added this to the Pipeline, Assets & IO project 2023-02-09 15:40:02 +01:00

Bastien Montagne removed this from the Pipeline, Assets & IO project 2023-02-10 12:49:18 +01:00

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OBJ Exporter does not save the interpolation used in a texture #101182