Export CT-AAA2 from 3d Slicer

Operating system: Win 7
Slicer version:4.8.1
Expected behavior: Export an OBJ (as seen on screen)
Actual behavior:No option to export (or in one case a 0 byes .OBJ)

Hi, first time caller and I’m having problems exporting an .OBJ from a CT scan. I have no medical background and all this is very new to me, maybe someone will be kind enough to point out where I’m going wrong.

Here’s my method:
I got the CT scan from here, I had to convert it to a nii.gz file with dcm2niigui that comes with mricron.

Drop the nii.gz file into 3D Slicer
Add Volume Rendering with the input set to the new file, click the eye open, choose the preset Bones (say, CT AAA2 or CT-Fat) I basically want to export out three obj files, skin, bones and fat respectively.

And this is where things get fuzzy:
Click Editor, add generic anatomy colours.
Click Make Model Effect, click apply (wait a moment)
click Go To Model Maker
in Models click create new Model Hierarchy
in model Maker parameters
uncheck generate all models
check filter type to Laplacian
That should allow me to save polydata that I want. Only it doesn’t and I’ve tried for several hours now and I’m not getting any closer to what I want. Which is essentially exporting what I see on the screen (bones, fat) as an obj. I’ve managed to do the skin layer by using ThresholdEffect, but that’s about it

Can anyone help me out?

You can start with this tutorial and video:


Note that what you visualize with volume rendering may appear as a surface when viewed on a 2D screen, but it is actually a surface-like rendering of a semi-transparent point cloud, and therefore it cannot be “saved” as a surface mesh. You must segment it if you need it as .obj or .stl, as Steve described above. See this post for more detailed explanation: Save volume rendering as STL file.