Operator to Load Daz Default Scene

[Midnight Arrow]

This is an evolution of #1044.

One criticism of #1044 was that users may do tonemapping in Daz Studio, and it’s too complicated to convert that. But I myself don’t care about tonemapping in Daz since I export everything. All I use is the default HDRI scene to compare materials after converting.

My improved proposal is to add an operator that loads the Daz default HDRI and matches its colors. Since it is the default in Daz Studio, the user’s hypothetical tonemapping is irrelevant. All we have to do is match the HDRI’s colors with the histogram using a render taken from the same camera.

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It’s not perfect but it’s good enough for quick material comparisons.

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After some testing I arrival at the values of standard view transform, medium low contrast look, 0.6 exposure, and 1.0 gamma. The color curve has two points at (0.15, 0.18) and (0.38, 0.48). The green and blue curves have one point each at (0.48, 0.48). The red curve is unchanged. That’s the best I came up with without needing to open the compositor, though it can probably be improved.

[Alessandro Padovani]

Again this is an attempt to match the default tone mapping in daz studio.

About your procedure with the histogram it may work but you have to take a camera angle that includes the darkest and brightest parts of the hdri. Also those parts should be large enough to affect the histogram. So multiple cameras would be a better match. Then a (0.48,0.48) point does nothing since the default curve is linear.

This was already proposed in #22 but we didn’t make it because the tone mapping in daz studio may change from the default.

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p.s. Though personally I don’t think that fiddling with the rgb curve is a good idea, because you match an image that contains only a subset of the rgb space. Unless you also include the srgb check in the image to compare, as in #22.

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[Thomas Larsson]

I don’t know anything about tone-mapping, but making a button for loading a specific scene seems unnecessary. Can’t you just import your background scene once, and then make it your default start-up scene in Blender, so you always import your character into your preferred scene?

[Midnight Arrow]

In theory I can, but I don’t want that as my default scene because I only use it to check materials. And me changing my own default scene isn’t going to do anything about the flood of comments/forum posts elsewhere saying “Exported materials don’t look right!” “These materials suck!” “Diffeo characters aren’t lifelike!“ etc.

[Alessandro Padovani]

But we just wrote a blog post for that. Then if people doesn't read the docs and wants to rant freely it’s not that I personally care to babysitting them.

That said we could add an option as “default daz tonemapping“ in the global settings. But it has to be studied better, for the reasons I explained above I don’t think your parameters are good. Testing a single case material is not enough we need a more complete scene as in #22. Plus some tests with translucency and different light conditions. Again this is a complex matter.

edit. note. Unless we go for a “rough approximation“ in that case using standard + med-low contrast as explained in the blog is close and we don’t touch the exposure and colors. But this will not stop people to rant because “it’s not the same as daz”.

[Midnight Arrow]

It’s not so much the ranting as it is having to explain to people (some who barely speak English) they need to import the Daz default skydome and set the tonemapping to an approximation of Daz’s if they want other people to troubleshoot their materials. Having one button to give people a baseline for comparison would help.

[Thomas Larsson]

I’m not sure if this is what you asked for, but in the last commit there is an option to add a default environment (the ruins HDRI) to any scene when it is imported. Provided that this environment is imported correctly it may give the right lighting. You can of course easily add the environment and tonemapping in DS, but I found it convenient when I forgot to do so. Which I usually do.

[Alessandro Padovani]

@Thomas. No that’s not what Midnight asked for. He’d like to have an option to set the color management to mimic the daz studio default tone mapping. That’s not easy to do and the settings suggested above by Midnight are not good.

The idea above to match the histograms of two iray and cycles renderings of the default hdri, is another way to try to match the default iray tone mapping. But it can’t work for the reasons I explained above. It’s not true that it doesn’t depend on tone mapping as Midnight is supposing.

What we may do is an option in the global settings to set the color management to “standard“ view transform with “medium low contrast“ look, as explained in the “tone mapping“ blog post. This will not be the same as daz studio but is getting close.

https://diffeomorphic.blogspot.com/2022/06/tone-mapping.html

• option: “daz studio default tone mapping“
• tooltip: “tries to mimic the daz studio default tone mapping, with some approximation“
• action: sets the color management to “standard” view transform with “medium low contrast”, may improve in the future if we find better settings

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p.s. Then personally I believe the blog post is enough, but it doesn't harm to have a extra option.

[Midnight Arrow]

I decided to put this issue on the backburner while I focus on getting materials down right instead.

[Thomas Larsson]

This commit is reverted.

[Alessandro Padovani]

It is very complex and not particularly useful to try to match exactly the daz tone mapping. As tone mapping is usually done in post or is application specific anyway.

A blog article has been written on this.