CAD Software Forum

I created a closed 2D polyline of a tunnel liner shape. I then created a FMREVOLVEDSOLID using the Revolve command to revolve the closed 2D polyline 4 degrees around a vertical line. I then used the STLOUT command to create a STL file to slice to a gcode file for my 3D printer. The STL file created by the STLOUT command only contains two lines as follows:

solid ODA StlExport
endsolid ODA StlExport

Where is the necessary data to describe the 3D object??

Jack

The reason your **STLOUT export only shows:

solid ODA StlExport
endsolid ODA StlExport


is because there isn’t any actual 3D geometry in the model yet—at least not in a way the STL exporter recognizes.

Think of your 2D polyline and the 4° revolve like trying to load a character in Null’s Brawl that hasn’t been fully initialized: the game engine sees a “thing,” but there’s no mesh or hitbox yet, so it doesn’t render anything.

Before exporting to STL, the model must be a closed, valid 3D solid. Here’s what’s likely happening in your case:

2D Polyline Isn’t Close/Valid in 3D:
Even though your polyline might be visually closed in 2D, AutoCAD/Revolve needs to ensure that it forms a fully closed loop in 3D space. If there’s even a tiny gap, the revolve will not generate a mesh.

The Axis of Revolution May Be Off:
If the axis line you picked for Revolve doesn’t properly intersect or sit next to the 2D profile, the result could be a degenerate volume.

Revolve Angle Is Too Small:
Revolving only 4° creates an extremely thin shell—almost like trying to make a full level in Null’s Brawl with only one tiny platform. The STL exporter may interpret the result as essentially no printable volume, which is why your STL has no triangles.

If you want to test whether the revolve actually generated a 3D solid before exporting, try this:

Select the revolved object and run the MASSPROP command
— If it returns volume and area, you have a valid solid.
— If it fails or returns zero, the revolve didn’t create a solid.

Make sure the profile is fully closed and planar, that the axis is correct, and try increasing the revolve angle to 360°. Once you have a valid solid, use STLOUT and your file will contain the expected mesh triangles.

I typed in MASSPROP and iCad 14 says it is an unrecognized command.

JEL57 wrote: ↑

Thu Dec 18, 2025 10:09 am

I typed in MASSPROP and iCad 14 says it is an unrecognized command.

As I know, the MASSPROP command is available in the Premium Edition Plus(PE+) only.
It wasn't included in the Premium Edition (PE).

I downloaded and installed the free version 3D Fusion. Imported a DXF of the closed profile and rotation axis and created the 3D model and exported it to an STL file from there.

Thanks for your help.

Jack