Hi Dave, could you please also post a 3DM model file with the curves in it that you are lofting?

That would help because I could then take a closer look at the actual geometry. It is hard to really examine things properly just from a screenshot only.

Usually if you don't get caps on something it means that the curve is not closed or is not planar.


It looks like the method you're using should be fine, but possibly a more controllable way would be to use extrude and then some control point manipulation.

To do that, do an extrusion but turn "Cap ends" off so that your extrusion only has the side wall parts and not the end caps on it.

With that object you can then select it and turn on surface control points by Edit / Show pts. Then select the top set of control points from the side view, and then switch to the Top view and rotate them. That will introduce a twist to the extruded part, and then you can select it and run Construct / Planar to cap the ends off.

The reason why you don't want to have the caps initially is that a cap is a trimmed surface and you can only show control points for joined surfaces if they are all untrimmed where they join each other. See here for some more description on this: http://moi3d.com/wiki/FAQ#Q:_Why_does_show_points_work_for_some_objects_but_not_others.3F


Let me know if you would like some more details on this Extrude + point manipulation method.

- Michael

I just lofted between 2 of them, then I can rotate the one side and history will update and twist them. This can be done with caps on to eliminate one step. :)

Have you noticed that the center dips down like you are wringing it? It looks ok to about 20 degrees. I'm going to try something else real quick

I think I got it.... I was thinking in the wrong terms for sweep. take a look. you can see that I used the profile of the gear as the profile and created 2 helix curves to use as rails. before when I tried this, I was only using 1 helix as a control curve for extrusion... what do ya'll think?

Hi nc dave. I was just going to post for you the top view of a sraight line sweep. The red is the old sweep path. The green would have to be the new one to have it stay flat on the edges. Looks like you have that figured out though.

Hi Dave, your 2-rail sweep results looks great!

Is that a solution for you then? Please let me know if you are still stuck.

- Michael

yes, that is the solution. Its so fast. I think I can make gears in about 50 seconds. When I get my steam punk mecha done, I'll post.

Thanks for all the help and all the effort you put in with your uses. this forum is amazing. I hope MoI becomes what you want (profitable, etc.). I know I will continue to be a supporter.

Useful thread for reference and lovely work Dave.

>created 2 helix curves to use as rails

Another way too. 2 rail sweep: use 1 helix curve + 1 line from centerpoint to centerpoint.