CAD-like fork of blender?

I’ve been on the national IT expo presenting the open-source free cybercafe/place where i work at. Mostly i was there to present blender. And there was quite some interest in Blender (and Linux, but that’s a different story).

Something i’ve heard a couple of times from older guys was “Is this similar to CAD?” …and i’ve thought a bit about it …blender could be forked into a CAD-like app. It’s already got some physics (game engine) implemented, and there’d be probably quite some interest in a free (open-sourced!) *CAD, especially since *CAD are usually quite expensive.

Just a thought i had, nothing serious. :-?

That would be great. Blender has spoiled me – dealing with proprietary software like AutoCAD is very annoying by comparison. I would even volunteer to work on such a fork, although I am not certain how much I could do. As it is now, I often build 3d models in CAD, and then import into Blender to finish it up, so I think this would be a good extension. However, it might be an uncomfortable fit for others.

It would have to be one serious fork !

It is the professed opinion of Ton and seemingly others that Blender is not to be built for CAD like work but artistic work, for intuition rather than precision.

I’d love some more control as it is quite needed for architectural presentation.



I like the idea of more CAD like functionality in Blender - then again, if you have a separate fork you loose out on the upgrades (at least you need to have someone continually working to keep things in synch if you want the upgrades).

I’ve been working on a fairly detailed house model over the last few months in Blender - I haven’t found the actual precision as such to be an issue (I’m working in metric, so I’ve been using 0.1BU = 1M, and I could easily have used 1BU = 1M thinking back on it).

Maybe we should think about actual CAD functionality that would be useful and wouldn’t interfer with Ton’s vision for Blender. For example the ability to use different units…

Any thoughts? If we can come up with a list of things we would like, and justification for them, maybe we have a chance of eventually getting them implemented, given enough support…



maybe implementing it as an option into the already existant blender would be the best option. this way we avoind a fork (and the separate upgrading) and we don’t meddle with the classical blender-touch.

i imagine it like blender engine is implemented, but then again, i haven’t pampered much with the engine yet :?

So: what CAD features would people like (in an ideal world!)?

I’ll start the wishlist:

Use of units apart from blender units - the idea would be that you enter a conversion rate somewhere in the user preferences (say 1 bu = 1 foot).

Then when you move something, the values would be displayed using the relevant conversion rate. When you use the ‘N’ box, the values would be entered and displayed in the units you’ve specified. If you try to enter a value which can’t be exactly converted to blender units, the value would turn orange (for example). You could also set the grid value in whatever units you need. All values would be stored in the file in blender units, so it shouldn’t take huge amounts of modification to achieve.

You can already set the grid to whatever value you want.


Direct input of Dx, Dy, Dz, Rot (should be DRot)


2 vertices/objects selected --> distance
3 vertices/objects selected --> angle
4 vertices/objects selected --> torsion

already in 2.29

2 vertices/objects selected --> distance
3 vertices/objects selected --> angle
4 vertices/objects selected --> torsion

I don’t think Blender records the order in which you select the vertice, so this would be somewhat harder to do (except for 2 vertice/object).


Errr… What would the values for one imperial foot be? considering there are 12 inches to a foot? and blender units seem to use decimal or 10 bu per grid square?

this has been an issue for me for years… the opportunities i’ve passed, where this would have been great for the job!


You could set the grid small enough to be 1 inch. 12 grid would be 1 foot then.


Indeed Blender takes into account a much greate precision that what’s displayed in it : at least 6 digits after the point, likely more. Look for a discussion I had last weed with Stefano. So it is possible to set the grid to 1/12th of a Blender Unit without loosing much precision at all : all my exports to AutoCAD have alway been free of rounding errors until now but then again I build furniture, not satellites.

Have a look to the different screens I did set in this file if you want:


What about another approach – rather than a fork… Leave the underlying ‘engine’ intact and build a series of tools as python scripts. Or would this be to clunky an implentation?

I’m picking up some info on Python over the next few days so I can get started with the following:

1- dimensioning
2- a reference file manager(???)
3- a tagging utility for windows, doors, and the like…

These are my opening thoughts on the subject. What else?

RSVP & thanks,

John K.

Kosty, that sounds like a good idea!

Alexandre Rangel