I prefer to work in the 2D environment when possible. It’s easier to control factors, but there are times when the 3D sketch environment saves a lot of time, and times where a 3D sketch is simply the only option.

3D Tube Bend Render in Autodesk Inventor

One such instance is routing tubing from a non-orthogonal axis fitting to a mount on an orthogonal axis. I could have used multiple 2D sketches to develop multiple work features in order to handle the transition, but what a waste of time. Plus with those extra steps, the design history gets quite complicated and begging for update failures.

3D Bend

Using a 3D sketch to layout linear geometry and 3D Bend to control the bend transitions is quite easy.  In my example, I have both mounting axes, as well as 2D geometry which delineates start and end segment tube definitions. All I need is the stuff in between.

Autodesk Inventor 3D Sketch Geometry with Work axes

  • Create a 3D sketch, and ‘Include’ all the 2D geometry that is needed as a reference.
  • Draw Line geometry representing the linear segments that are needed in the transitions.
  • Constrain the lines as needed to the references.
  • Add Dimensional constraints as needed.
  • Create 3D Bend at each vertex.


Autodesk Inventor 3D Sketch Bend Geometry

Some Tips

In order for 3D Bend to work, all related linear geometry must be in the same 3D sketch. It will not work on geometry in more than one 3D sketch.

When you use the ‘Include Geometry’ tool, any geometries included can be used in a Sweep operation. In the video below, I demonstrate how included geometry can be used as part of the path in a Sweep. Note that if you want that included geometry to be ignored, just like in 2D sketches, you have to change their type to construction.

A path driven sweep will fail if your included geometry (non-construction) overlaps your sketched geometry. Essentially doubling back on itself. This will cause the Sweep to fail. Since the problem is covered up by well built line-work, it is often very difficult to discover this.

How Does It Update?

Brilliantly! I started with the tube ending all the way up to the flange, but realized that I needed room for a tube hinge  I simply adjusted the 2D sketch references for the gap needed and the updates behaved perfectly.

Autodesk Inventor 3D Sketch Tube Surface Transition

Video Demo on our YouTube Channel