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texture quality

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heikog

Hi Guys, 
I am still struggling with texture quality. as a pro bono thing I am doing a small old house - There is a small Graffity on the chimney that as a gag I would like to show in the model. however, I didn't succeed for now.
So if anybody wants to look into it, I attached the dropbox link to the source photos, a photo of the chimney-part and a screenshot of the model as well as the sketchfab link.
I'd like to understand if I do something wrong in photography, in using the software or if I have wrong expectations anyways when it comes to texture quality.
any input highly appreciated.
https://skfb.ly/6CV9O

https://www.dropbox.com/sh/e1wf2iptuv631eq/AAAsTKk2o0HngmMCDWKZfWGGa?dl=0

Thanks in advance

Heiko



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  • Avatar
    Jasper Mink

    Hi Heiko,

     

    In RC, when you look at the "Texture quality" percentage for this model, what does it say?

    The 3D viewer inside RC does not show the full uncompressed model quality but a down-sampled view for increased performance.

    If you use the Render function at the export ribbon you can export a full quality screenshots of the current view. Would this screenshot be just as blurry as Sketchfab? Sketchfab also has an upload limitation on texture files.

  • Avatar
    heikog
    • Edited

    Hi Jasper,

    thanks for looking into it.

    The texture quality on the sketchfab model actually says 42% - so that is the issue I assume? (texture utilization is around 70%)

    The "full size" model before RC optimized it for Sketchfab has 111% texture quality - and now that I checked the writing on the wall is perfect - however, on export, this model is about 4 GB. 

    So is it a trial and error process to get a balance between texture quality and file size ?

     

    I could live with texture quality of 40% on most parts of the model - just some parts need to be high res

  • Avatar
    Jasper Mink

    Hi Heiko,

    It says 42% of the optimal texel size. The optimal texel size is calculated based on the average GSD of the project.Assuming you created a single texture for the sketchfab model with a resolution of 8k (maximum texture resolution that sketchfab allows) then this single texture file is roughly half of the maximum achievable texture resolution.

    Texture utilization is something you preferably want to get as high as possible but from what I understood you'll never reach 100% with the unwrap algorithm that RC uses, which is fine for most purposes.

    In what format did you export the file that it's 4GB? Is it 4GB for the model or in total with the texture files? Preferably for a building like this the whole model should be less than 200MB. What's the polygon count?

     

  • Avatar
    heikog

    attached you will find the 2 Mio model and the sketchfab model. the 2 Mio model with jPeg exprt of textures is about 400MB

     

     

  • Avatar
    Jasper Mink
    • Edited

    Ah you've used the "Upload to Sketchfab" tool while letting RC optimize the model for Sketchfab?

    I'm uncertain in which way exactly RC optimizes the texture for Sketchfab. And I have not yet been successful importing several 8k texture for a single model in Sketchfab, I don't even know if that's even possible.

    But seeing as Sketchfab prefers a single count 8k texture you'll end up with a higher quality if you generate a single 16k texture and then downsample it yourself in Photoshop to 8192x8192 and import it alongside your 200k polygon model into Sketchfab through your webbrowser.

    You can do this by setting the unwrap parameters to this:

    And you can end up with this kind of quality within Sketchfab:

     

  • Avatar
    heikog

    Hey Jasper,

     

    thanks so much for all this info and insight - very helpful. Ill go through your tips and keep you posted about the results

    best

    heiko

     

  • Avatar
    heikog

    btw: why is it better to buil a 16k texture and scale it down to 8k in PS instead of generting a 8k texture in RC ?

  • Avatar
    Alexandiir

    You can upload models to Sketchfab with more than 1 texture files. This example with 8x8k jpg files.

    https://skfb.ly/6BKU7

  • Avatar
    heikog

    I’ll try that. Thanks

  • Avatar
    Jasper Mink
    • Edited

    Aleksandr Gorky - Thanks for this information. Initially when I tried this I kept on receiving errors. I thought it was due to the multiple texture count. After trying it now it uploaded without issues.

     

    @Heiko, downsampling From my expeirence, a 16k texture down-sampled to 8k usually results in a slightly better quality than generating it on 8k. Although it's nearly neglectable.

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