Assembling parts


I’m a newbie with 6-8 hours into tutorials, and have only used 2D programs before.

Is there an explanation somewhere of a methodical way to assemble parts? For example, I have made models of a wheel and an axle, and I would like to insert and center the axle into the wheel hub. I managed to do it, but it seemed quite awkward, and took too long, with lots of mousing, orbiting, trial and error.


You should have a look at the inference system, most of positioning tasks only need this in combination with the move tool. You can use plugins like CenterPointAll (TIG), Guide Tools (Thomthom), … to add construction points for reference.


Also keep in mind the cylinders are actually regular polygon prisms. There are endpoints all around the circumfernce at both ends, which you can snap to their corresponding end points on the other part rather than trying to align them by using centers.

Still, if you need to find the center of a circle or polygon quickly and have no other means, just draw a line across corners of the polygon and use the midpoint of the line as a center.

Turn on the X-Ray display style to help you align centers that are hidden behind their parts.



That helps. Thanks for the ideas.


In may instances, it can also help to draw objects in place. in other words, draw the axle right where it belongs, then draw the wheel directly over the axle. That will eliminate the need for all that mousing and orbiting. Also, get in the habit of working with components: Once you’ve drawn the axle, make it a component. Once you have the wheel, make it a component, too.
Hope that helps.


I’m afraid I must disagree. I don’t think that makes much better sense than fabricating a wheel in place on an axle in the real world. At the very least, the two parts would get in each other’s way as you work.

If you must model items in place to get them assembled correctly, it suggests to me that your skills with inferencing need strengthening.



Dear Gully_Foyle,
I’m afraid I betrayed my woodworking background in my forum reply about drawing things in place. It’s a technique that works well when creating, say, a model of a chest of drawers or a chair. Drawing in place does save time–no need to move things that don’t need to be moved–and it helps ensure accuracy. No need to measure things that don’t need to be measured. Obviously, not everything can be drawn in place, and in those cases it helps to have good inferencing skills.


You can use a component copy to work with, so the original stays in place and you can delete the copy after editing (I would call this Daves method :wink: ).


Actually Cotty, what you describe does take advantage of both methods at the same time.

One can model/edit the instance in place (to see it grow in the assembly or if at some point the other parts obscure your view you can also turn to the stand alone instance to model/edite that one. For both instances share the same definition.

Some tips for this “mixed” method:

  • set up scenes to quickly switch from one instance to the other, back and forth.
  • if required, work in a scaled up stand alone instance. The one in place (1:1) follows.