Texture losing quality after rendered to texture

[Anonymous]

Hi,

I am rendering my texture to use it for painting purposes in Mudbox but I am facing some quality issues.

This is how it looks before I render it:

This is how it looks after I have rendered it to texture:

Is there anything I can do to avoid this to happen?

Any help would be highly appreciated!

[Diffus3d]

Hello @Anonymous ,

In the top image, you are probably tiling the texture a bunch of times (or tiling 2 and blending between them with a noise or something to remove the obvious repeating), but when you render to texture it's taking your entire land mass and using the 1:1 uv space with no tiling.  Therefore, the resolution must be much greater to display properly.  

If 4096 x 4096 resolution still looks bad when you bake, then maybe baking the texture isn't the most efficient way to achieve your desired result.  What is the end goal?  Meaning, what is the issue that baking the texture is overcoming?  

Best Regards,

[Anonymous]

@Diffus3d , thanks for your reply. We were not aware of that rendering to texture is taking the entire land mass and using the 1:1 uv space with no tiling. This is great info, thanks!

Our end product is displaying the models in our Autodesk Forge Viewer application and we have found baking to be the best (only?) way to display the textures on the models. These are some of the facts we have found:

• Autodesk Forge Viewer only supports Scanline materials
• Adding a Standard Omni light with Area Shadows has proven to give the best results as far as shadow baking goes. This is an example of the result in this case: 
  • However, the model above is a smaller one and the bigger the model gets (more mass) the more blurred the texture will look when baked.

This is an example of a bigger model:

We are using 1024x1024 in that one. Would you say that it would be worth a try to test out the same texture in 5000x5000 or is there any other approach that would be more relevant?

[Diffus3d]

Hello @Anonymous,

Yes I think it's worth a try.  If you save it as png or jpg or a format that's not too large it probably won't cause too much of an overhead issue.  It should look quite a bit better than the 1024.  

EDIT: I should mention that it fills the 1:1 space when using the default "use automatic unwrap", or does the best it can.  If you don't like the layout, you can create a 2nd uv layout with the whole shell packed in channel 2 an bake that into channel 1 but just changing the object channel in the render to texture dialog. 

Best Regards,

[Anonymous]

Thanks for your reply @Diffus3d 

Here are the results:

Baked 5000 x 5000 (tiling 20/20):

Baked 1024 x 1024 (tiling 20/20):

5000 x 5000 does indeed displays a better baked results but it does this have some potential.

I think I will try your other suggestion:

• If you don't like the layout, you can create a 2nd uv layout with the whole shell packed in channel 2 an bake that into channel 1 but just changing the object channel in the render to texture dialog. 

Do you know if there's any tutorial out there related to what you are describing here? I'm fairly new to this kind. Thanks a lot

[Diffus3d]

Hello @Anonymous ,

5000 x 5000 is a weird resolution, power of 2 is typical, such as 4096 or 8192.   I don't know if that might have a negative effect in Forge... it might.   Also, at high resolutions you might have to check the texture in your final application or press render to see the actual texture result.  (Or update your viewport texture res in Viewport Configuration -> Display Performance.)  

I'm not sure if there is a tutorial specifically for baking between channels, but the process is simple.  I can type it out in a few steps:

1) Make sure your CH1 uv's are collapsed into the model.  For good measure, put an unwrap on the model and Save out the current UV's into a file using the Save UV's function.  

2) Create a CH2 in the Unwrap UVW modifer by changing the channel to 2 in the Channel rollout, and select "Abandon UV's". Lay out your CH2 Uv's as you want them within the unwrap window while in CH2, making sure none of them overlap.  (If you accidentally laid out the new uvs on Channel 1, no biggie... just save the UVs out again but name them Channel 2, then load them into Channel 2 in the unwrap.  Then collapse, and load the original channel 1 uvs into channel 1 on a new unwrap modifier.)

3) Then collapse the unwrap into the model.  Now both Ch1 and Ch2 are collapsed into the model. 

4) Go to your Render to Texture, and under "Mapping Coordinates", select "use existing" and use "Ch2".  Now when you bake, it'll bake the textures of channel 1 into channel 2. 

I use this all the time when I need a clean projection from one angle onto the uvs for another.  For example:  to get a good projection of maple leaf onto this guy from the front and baking it onto his regular texture uv's which matched a bunch of other characters.  Meaning, I didn't have to re-uv him and repaint all the muscles, I just baked the leaf from a planar projection 'front' onto his already laid out uvs, color it, and put it on multiply in photoshop.  Cake!

Best Regards,  

[torbjorn1]

Thanks for your reply @Diffus3d 

It ended up giving me a good result, however when I transalte it to SVF (the file format that the Forge Viewer uses), it looses quality/resolution. See image below:

What's interesting is this, in the Standard viewport (without any rendering), it looks like this inside 3ds Max as well - exactly similar to how it looks in the Forge Viewer (the brighter coloring is due to Forge settings):

Could this mean that the Forge Viewer reads the compressed view just like the viewport in 3ds Max does without hitting render and displaying the good settings/resolution?

[Diffus3d]

Hmm, there may be a maximum texture size in Forge.  I don't know the application so it's hard to say... maybe you could split the ground up into 4 objects and use 4 maps or something in that case.   I wish I could offer more suggestions for Forge, I apologize.  

Best Regards,