How to model in Blender like AutoDesk Inventor?

Are there ways that I can constrain things to be tangent, equal, parallel when doing simple modeling?

Is there a way that I can “size” (dimension) things? I’m more of an exact person when it comes to modeling; it seems to make my life easier… but not in this case I guess.
I’ve used Inventor, Solidworks, and Rhino… and these all have constraint options.

Like… for instance… making a circle tangent to a square’s edge. Circle radius 1 and square edge length equal to the circle’s radius.
I can’t figure out where to find how to do these things. (Google and forum search has failed me.)

Blender isn’t really geared toward exactness. It was made to function efficiently as an artists tool, so eyeballing is the standard. However, If you press N, while in object or edit mode, you will get a panel for numerical entry. You may also wish to look into blenders various snap functions, for snapping to the grid, or other things.

I have written some tutorials on applying a CAD like work-flow to Blender that might help.
Blender Precision Modelling Guide

When you start talking in terms like, “make a circle tangent to an edge,” you’re speaking in CAD terms. You’ll find that CAD packages specifically support that model, while 3D packages such as Blender really do not. The intent of the two products are different.

At times, it is very convenient to use a CAD package to generate a model which is subsequently imported into a 3D package, whereas going in the opposite way really makes no sense. The trick is to, “use the tool that is intended for the job you have.” Don’t ask Blender to do what a CAD package does, and don’t ask a CAD package to do a rendering good enough to drop into a movie.

Great information as to setting the accuracy. We all now it has the precision, just a few more step to get to considering machine type CNC Cad/Cam. But blender will do it quite well.
I was just wandering if you have a plan to release a version for B2.53+.
Thanks for your great efforts. I look forward to having this built in in the future as an add-on tool.

What would be impressive is the preset start up option from the splash screen. Right now we have Blender,Maya, (Next)Cad/Cam Dems, or to that idea anyway.
Thanks again.

Yes I will update it at some stage when I can find a way to make all the tools work. This style of modelling relies heavily on using the knife tool snapped to reference vertices to get the knife cuts placed correctly. I haven’t found a way to do this in 2.53 yet.

Yea things seem to be changing very quickly with 2.5. That is good though.
Thanks again for the tutorial.

Use Sketchup for that and then import it into Blender. Or you can spend several thousand dollars to get AutoCAD 2011 or Microstation V8i (Select 2) and do your modeling in there. I use Microstation at work and AutoCAD at home. Both are excellent but extremely expensive options. Why bother when Sketchup is free?

hi there,
is it what you are looking for?
the CADtools script for 2.49b in action: video