Question: Optimizing resolution using Optimal Texel Size and normal maps

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    Erik Kubiňan CR

    Hello Benjamin,
    thank you for taking your time to place your question clear and specific.

    To the first question, the optimal texel size should be calculated based on the scale of the model and the polygon count as far as my knowledge goes. Therefore as you questioned, the two models could differ in the unwrap results as they have very different topology.

    The second one. Here I am not sure if I got it right. But anyways, RC calculates it with the same method as most of the softwares out there. It is ray casting based on an average search distance between the source and the target model. The result of the normal map is just the difference of the two surfaces written into the pixel values. The higher the resolution the more micro detail of the source model is projected and then rendered on the simple model.

    To give you a simple tip which I use in my workflow that helps the last sentences of yours. Export the hires model for surface cleanup, bring it back to RC. Simplify it to about 3 or 5M and let it out for the texture cleanup, then bring it back and reproject the diffuse texture onto the hires cleaned model. Then you can simply create the optimized model of the last one and have everything correct.

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    Benjy

    Hello Erik,

    Thanks for your detailed reply. How does scale influence optimal texel size? It would seem arbitrary to think that just because the scan is of something big or small, their might not be a need or interest in preserving the finest details, given a virtual camera might closely graze either environment.

    To further clarify, recall in my case I had unwrapped for optimal texel size in the hi-res model to yield three 8K maps. Say I hadn't done that, instead went ahead to simplify to lo-res model, would Unwrap using optimal texel size then be based on only the lower res model of this component? If so, is it possible it would still yield the same three 8K maps? I can test this of course, just curious. Given the amount of redundant information in the hi-res model within the smoother areas, wouldn't that predict that with simplify, which is adaptive and thus will lower the relative poly count in those smoother areas, that optimal texel size might stay the same down to some lower threshold? If that makes sense.

    I'm unclear what you mean with taking a simplified model "3 or 5M and let it out for texture cleanup". Do you mean run that mesh through 3rd party app to further clean geometry?

    Thanks.

    Benjy

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    Erik Kubiňan CR

    Well I am more of spreading my thoughts here, I don't know the whole algorithm, but it makes sense that if model is large, it would need more textures for example, that is the job of fixed texel size as well.
    Regarding your question to the simplified models. I believe the tool always works with the information of the selected model and no other. I doubt it would consider the texel size based on the source one rather the one you've selected.
    Yeah, that is what I meant. Said that cause I know you use such apps in your workflow due to a video from you, so I thought I could give a tip.

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    Benjy

    I'm curious what kinds of edits you're working with when round tripping textures and why not do that after final export, why the round trip? The UV shells being organized the way they are, for rough topology it's obviously next to impossible to discern features for editing in order to target them, assume you're doing some kind of global adjustments?

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    Erik Kubiňan CR

    I don't want to go too deep into the postprocessing as this is not the correct place and neither my position is. I will contact you directly and may give you some overview on this to make it clearer.

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