@lminardigmail wrote:
Explode the solid, give the SURFSCULPT command and then select the surfaces that define the interior "watertight" void. This will create a solid object of the interior void.
Lee
Thanks Lee for the tip. I will try it out. Right now, the Solid is really complex, but I hope AutoCAD will not complain. I'll get back and accept solution or complain 
@Alfred.NESWADBA wrote:
Hi,
>> that I get a Solid for 3d print
May I ask a question just out of curiosity ... why is it constructed hollow when you need to 3D-print the object and so you have full control using the infill parameters?
- alfred -
Hi Alfred,
Yes, I need the infill to be controlled by the 3d Print application. I use Cura which comes with the Ultimaker 3 printer.
If the model is hollow, it gets filled up with support material which I think might be unnecessary. If I don't fil it up, I fear the model might end up fragile.
I wish there was a tool that could simply tell what to print from the outer shell.