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Dear Freesurfer Community,
I use Freeview to render 3D views of overlays on cortical surfaces. For my current processing, the absolute scale of the overlay map is important, and this absolute scale is distorted / marred by the shading that Freeview adds due to its default light source. (E.g., the top of the image is lighter than the bottom.)
My question is this: is there any way to change the default light source of Freeview? I would prefer to use a uniform ambient light that did not cast any shadow, such that each pixel’s rendered intensity was exactly correlated with the absolute value of the visualized overlay in that pixel.
If this is not possible, a point light source “at infinity” pointing directly into the plane of view might also suffice, since I believe it would produce a uniform illumination on a spherical base hemisphere. (I could be wrong here.)
One final note: ideally this method would be possible to achieve by the command line, or failing that, to manually change in the GUI such that the setting would be preserved upon quitting and restarting Freeview.
As always, any help is much appreciated. If someone happens to know that this functionality is absolutely not available, I would certainly like to know that, too.
Thanks in advance.
Sincerely, Sam Johnson Postdoctoral Scholar Brain and Education Lab, Stanford University GSE