3de -> st maps

Is it possible to use matchbox to interpret 3de lens distortion files to make st maps in flame?

T@gging people I think might know the answer but please jump in if you know the answer:
@cnoellert @lewis @ALan @Stefan @Slabrie @fredwarren

3de provides a matchbox to do distortion. If you put an stmap image through it you can “bake” the un/distorted stamp to use is without the matchbox. The Colour Source node works fine to create a source stmap… just make sure is 32bit.


I never thought of that. Thanks. I’ll give it a go. Do you just set the colour source to the uv setting?

Just set the color source to a quad gradient so in the red channel is a ramp that goes from 0 to 1 left to right across the width of the image and same for the green channel but bottom to top. Basically describing the 0,0 1,1 UV coordinates. Blue channel has no effect but sometime I like to color it solid blue to differentiate between changed and unchanged UVs.


You can also use their matchbox shader to output a STmap natively.

Screenshot from 2023-10-02 13-12-18

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So… I have to say, I haven’t done it this way before. Our process for generating the STMaps always calls for Nuke to be brought in to the mix.

Are you saying that from 3de you can get a matchbox and/or STMap that allows for the overscan area needed to avoid losing data?

I believe that was discussed here: Issue with STmaps from Hotsprings

There’s a way of doing the overscan / bounding box in 3DE as well, but it involves a manual step. Don’t have it in front of me right now.

That’s the export screen in 3DE for Flame. Note the Overscan Margin entry which defaults to original size. You have to determine the bounding box (or use reasonable default %) and update these during export, then it should work.

Screen Shot 2023-10-02 at 10.20.02 AM

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With the 3de export in nuke you get a wisywig view. I’ve used the guesstimate step with the matchbox before. It’s not ideal. But it does work quite well.

Hadn’t notice this before, but in the calc menu there is a script to compute the overscan:

In the overview menu you can also have it visualize it on screen, though it doesn’t have a read-out of the size in that view.

Would be nice if they had a button in the export dialog that just ran that script.