Fit vector displacement.

Started by paq, December 21, 2017, 12:12:07 pm

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paq

December 21, 2017, 12:12:07 pm Last Edit: December 21, 2017, 12:19:59 pm by paq
Hello,

I have a vector displacement texture (.exr), normalized, and I need to refit the value between 2 specific Min/Max value. Is it possible to do that with the blue nodes ? I don't see any refit operator, and I'm too dumb to recreate the maths myself :S
Gameloft

Hetzen

Can you use a colour adjust and set the black and white points to your range? You may want to un-check clamp black and white.

paq

Hello,
Well I finally use this :

OLD PERCENT = (x - OLD MIN) / (OLD MAX - OLD MIN)
NEW X = ((NEW MAX - NEW MIN) * OLD PERCENT) + NEW MIN

Seems to work fine with vectors.

I have tried the color adjust, but it very difficult to enter color value like : 0.811485, 1.25989, 0.903355 with the actual interface.
Gameloft

Hetzen

Glad you found your solution. Can you explain why you wanted to do that?

paq

Hi Hetzen,

It's for the vector displace project here : http://www.planetside.co.uk/forums/index.php/topic,23959.0.html

I can't find a way to write negative value in .exr when exporting my vector displace data from Houdini (something that bugs me a lot grrr), so I refit the range between 0-1 before the export, and I had to refit the value back in Terragen between the original min/max value.

Gameloft

Hetzen

Hey Paq

Thanks for explaining. Yes I've been following your thread. I'm keen to try your method out.

Something I do, which may not be relevant here, is when I want to raise a normalised -1 to 1 range into the positive I tend to add 1 then multiply by 0.5. So the new range is 0 to 1, the old zero point is now 0.5. This can be useful to put a curve on the graph shape with bias or gain scalers amongst other uses. Then to bring back into -1 to 1 range, simply multiply by 2 then subtract 1.

paq

Hi Hetzen,

Well, for my first prototype, I didn't pay attention to the size of the model, so mix/max value could be way over -1 1.
I'm such a noob for this kind of stuff  8) ... but now I do my normalization in Houdini before exporting, so whatever the geometry I create, x/z always fit between 0 and 1 ... so I shouldn't get to much trouble to get the right result in Terragen.

Gameloft