BrainVISA

Hi,

I am using Anatomist ver.3.2.1 on osx. While other functions work well, the volume rendering seems not working. What I tried is to load T1 volume data and select <Fusion> menu and select <VolumeRenderingFusionMethod>. A VolumeRendering object was created and I put it into the 3D window and nothing happened. Could you help me? I read several documents in your website but I couldn't find the solution or any related topics.

Thank you.

Hi,
In Anatomist, volume rendering is implemented using OpenGL, and technically uses many many parallel transparent slice planes accross the volume (at least one per voxel, so it depends on the resolution of the volume), so it can be quite heavy for 3D cards. Moreover it is using 3D texturing, which some drivers/cards don't do well even if the driver claims it is supported by OpenGL. So it may work on one machine and not on another one. It works on our Mac on a standard MRI volume (256x256x124 voxels).
There are some ways to limit the planes sampling accross the volume in the volume rendering object properties, or you may undersample the volume before loading it in Anatomist if it is the cause of the problem.
Denis

Hi,
I just tested volume rendering with some low resolution volume image and saw it worked. Thank you for your help. Someday, I hope Anatomist can handle higher resolution volume data on my MBP. ^^;

Thanks.

Well, normally undersampling should take place when the volume doesn't fit in the 3D card as a 3D texture, but either the limitation has not been detected, or there is a bug in anatomist. As for our needs we always use smaller volumes, maybe I didn't take a chance to really test it...
Denis