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bene51 / 3Dscript

Create 3D/4D animations using a natural language-based syntax
https://bene51.github.io/3Dscript
BSD 2-Clause "Simplified" License
58 stars 12 forks source link

Feature Request: Better alpha mapping #15

Open Sethur opened 5 years ago

Sethur commented 5 years ago

As I understood it, right now, alpha can only be set in the form of a curve that is 0% (no transparency) at some minimal voxel intensitiesand 100% (max. transparency) at some maximum voxel intensities. Additionally, the curve can be made non linear by defining a gamma value.

There seems to be no way to - for example - invert this curve (i.e. make dark stuff transparent and bright stuff opaque) or set it to some fixed value for all voxel intensities. Also, one cannot define a starting and stop value for the transparency.

It would be very nice to have some more flexibility when it comes to alpha LUTs.

As a starting point, an optional definition of alpha_start and alpha_end would be a big help already.

As a second step, a way of defining several nodes for the alpha value with defined interpolation would be great, for example like this:

At frame 0 change all channels' alpha at intensity 500 to 10%
At frame 0 change all channels' alpha at intensity 600 to 20%
At frame 0 change all channels' alpha at intensity 800 to 40%
At frame 0 change all channels' alpha interpolation to linear (cubic, gamma-like, etc.)

The crème de la crème would be a way of additionally defining different colors not only for different channels but for different intensity ranges. That way one could, together with the more flexible alpha mapping, define tissue ranges in 1-channel-only-images and make them look different (i.e. intensities A to B = soft tissue = reddish color, intensities C to D = bone = whitish color, etc.)

hiimwilson commented 5 years ago

Sort of going along with this, It would be awesome to have the ability to integrate different color LUTs or RGB colormaps into animations. Not 100% necessary, but would be really nice to have.