Hi Chris,

Lately we found that the overlayDepth parameter can change the additive blending results a lot. I'm not sure why and what's the best way to present our findings.

We have three binary images and we want to present them together in one figure to show the common and distinct regions across conditions.
We found that when the overlayDepth was set to a relatively larger value like 10 for instance, the results are drastically different from when
it was set to 0. There were yellow regions indicating overlapping areas between condition1 and condition2 when it was 0. But that overlap
disappears when it was set 10, which i think is about the default value of this parameter.

Here is the code I used.

import gl
gl.resetdefaults()
gl.loadimage('mni152')
gl.overlayloadsmooth(1)
gl.overlayload('/Volumes/T7/Cond1.nii')
gl.minmax(1, 0,1)
gl.colorname(1,'1red')
gl.colorfromzero(1,1)
gl.overlayload('/Volumes/T7/Cond2.nii')
gl.minmax(2, 0,1)
gl.colorname(2,'2green')
gl.colorfromzero(2,1)
gl.overlayload('/Volumes/T7/Cond3.nii')
gl.minmax(3, 0,1)
gl.colorname(3,'3blue')
gl.colorfromzero(3,1)

gl.cutout(0,0,0.5,0.5,1,1)
gl.azimuthelevation(90,60)
gl.colorbarposition(0)
gl.shadername('OverlaySurface')
gl.shaderquality1to10(5)
gl.shaderadjust('brighten', 2.5)
gl.shaderadjust('surfaceColor', 0.6)
gl.shaderadjust('overlayOpacity', 1)
gl.shaderadjust('overlayDepth', 10)
gl.overlayadditiveblending(1)
gl.backcolor(255,255,255)

Thanks,
Chuanji