The interface, modeling, 3d editing tools, import/export, feature requests, etc

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Postby Jim » Sat Apr 19, 2003 11:35 pm

I was just wondering how possible it would be to add some CAD featues into blender. I do a Mechanical Engineering degree, and I have to use CAD a lot, but all the CAD software I have used so far (Rhino, autodesk inventor, autocad, autodesk viz) is unintuitive to use compared to blender which I have used for fun for a number of years now. The only thing that stops me from using blender for CAD, is that it is not accurate.
It would be realy cool if blender had options like dimensioning and constraining of objects. I am not talking about the realy advanced stuff like converting models to drawings, stress analysis or CAM, it would just be good to be able to use blender as a more precise modeler.
Does anybody else think these options would work in blender, or would they be too hard to implement?

P.S. For the accuracy needed for CAD, only NURBS will work anway, so these extra options would only have to affect NURBS objects ayway.


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Postby niket » Wed Jun 25, 2003 11:47 am

I Am Fully Agree with u and i also didn't find a way manually enter transformation like maya and 3dmax or any cad prog.
pelese tell me on if u find one :D

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Postby jazzroy » Thu Jul 03, 2003 12:17 pm

I've already posted similar whishes: easier way to model and transform accurately and also to have a on-the-fly snap.
Blender would have a chance to become a really useful CAD software!

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Postby ton » Sat Jul 05, 2003 2:14 pm


Can you more precise about it? Manually entering transformations for Objects can be done with pressing Nkey for example.

"Dimensioning" and "Constraining" probably are terms from programs you use. Best is to translate that to blender-speak, or a clear & simple proposal what we should add to Blender to make it possible.

A good location for feature requests is the 'functionality board' Tracker, which can be found here: ... 2&atid=207
The better you describe such a feature, the faster it can be passed on to the coders!


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Postby GrimDude » Sun Jul 06, 2003 5:26 am

In Autodesk's Mechanical Desktop you create objects by drawing a rough sketch in 2D, and then 'constraining' the object to the desired dimensions (fixing lines to parallel states, equating states between features, etc.) and THEN commit to extrusion, lofting, or sweeping to create the 3D base.
Jim, I understand what you mean by "unintuitive," however I don't think Blender is intended to be a CAD system (nor should it be). A push in that direction could take it back toward commercialism.

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Postby ideasman » Tue Jul 08, 2003 12:33 am

I agree, there should be a way of simply scaling x100 for example.
I am using scale as an example but grap, wrap etc could also be used.

the 'n' key only works for obgects and only gives you the absolute rot+size+pos. This does not help with scaling a group of verts.

If I want to scale a group of verts 1500% it should not be a case of twiddeling the mouse and zooming in until the number hits 1500.001

This is not an advanced CAD feature, its simple that sometimes its quicker to type in a num then fiddle with the mouse.

I would like to add this feature myself. the way I would do this is by being able to punch in numbers when in scale/grab/wrap mode. These numbers would change the xyz unless the user has constrained the change to only one axis.

This would also be good because it would be easy so scale to %0 - often used to align verts.

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Postby niket » Wed Jul 16, 2003 9:52 pm

Can you more precise about it? Manually entering transformations for Objects can be done with pressing Nkey for example.

Yes it is works only for Objects it should work also on vert in edit mode so group of selected vert can move. and Numpad dot key frame(zoom) object but it should work on selected vert like f key in maya it will be helpfull.

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Postby niket » Tue Aug 26, 2003 9:56 pm

check out this
good work of theeth related to this topic

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Postby jd-multi » Thu Aug 28, 2003 1:19 pm

Cool, that makes blender a more exactly modeler, where you can input variables to move object, really needed to make precious work in blender, like architecture. Then blender has this, more people will use blender.

Yesterday I found a article on a website about blender is battling with some another 3d apps, maybe if we can get some good sponsors, Blender will defently beat another 3D apps within some years.

Interesting article:

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Location: Italy

Postby Manuel » Fri Aug 29, 2003 9:44 pm

From we are talking about a BlenderCad
python script. The first can be a module called

Sorry, we talk in italian... :(

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More emphasis on CAD.

Postby dEs_iGn_eR » Thu Nov 27, 2003 1:28 am

Goal 3 of the foundation is "Make Blender a better product, and promote free access to 3D technology in general" notice the 3d in general part, i would like to initiate greater consideration for the CAD potential of Blender. Any suggestion that free for game use is somehow more noble than schematics or machine control is absolute rubbish! Who is to say that non entertainment type uses and product creation must be used for commercial means.

The world needs more altruism, with millions of starving people around the globe lets start a new push for Blender, feeding the masses; free!!

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Postby thorwil » Thu Nov 27, 2003 1:17 pm

In my experience some people fear that CAD means ugly, complicated software for engineers (not suited for designers or artists). Even if that would be the case for all available software, it still could be changed.

The other thing is that many people think that CAD features will not be useful for creating your usual stills and animations. While it's utility for characters might be rather limited, CAD functionality can make modeling furniture, vehicles and generaly all rather geometric/regular things much easier and more flexible.

One still might think CAD is only good for designing things to be actualy build. Rapid prototyping allows everbody to have custom 3d models transformed into real products. It might be a little costly right now, but prices are expected to come down, and some people already talk about desktop rapid prototyping. This will make freely available CAD capabilities much more attractive.

I know only a little bit about Rhino, but have quite some experience with Solidworks. Parametric, feature-based modeling is a must have for serious CAD, I think. I can go into as much detail as you want about what that means.

Solidworks uses a hierarchy (treeview). Does anyone know of a CAD app that uses a network (like
Houdini and Maya, far as I know)?

How's the interest in a sub-project to CADify Blender?

I will try to build a list of CAD features, starting with the most essential:
- Real units (mm)
- Numerical entry (extra: calculations in input fields)
- Dimensioning like in technical drawings. A way to define distances between lines, endpoints or centerpoints.
- Drawing tools for arcs: center+radius, endpoints+radius, 3point.
- Snap to grid, enpoints, lines.

Oh well, that should be enough for now.
I could work out explanations/proposals but I would rather like to hear how's the interest and who might implement this stuff. Since I still have to update my Toolbox and there's all the other Blender ui stuff at my site.

So how much CAD do people want to see in Blender?
Last edited by thorwil on Fri Nov 28, 2003 1:17 pm, edited 1 time in total.

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Postby knoxer » Thu Nov 27, 2003 4:14 pm

I am also a CAD designer. I'm having a really hard time learning Blender, so I'm not sure what is is already in there, but I have a few CAD-like features to request also (perhaps this would be a completely separate program? BlenderCAD?):


For 2D (sketching):

Parallel (make 2 or more lines parallel)
Perpendicular (make 2 lines perpendicular to eachother)
Horizontal (make a line horizontal)
Vertical (make a line vertical)
Equal (make 2 or more lines equal length)
Colinear (make 2 or more lines "line up")

Linear (for giving straight lines (or distance between any two points) a length)
Diameter (defining the size of a circle)
Radius (defining the curvature of an arc)

-Fillet / Chamfer (round off or cut off a sharp point in the sketch)

For 3D (once the 2D sketch is done):

-Extrude (Give the 2D shape depth, should be able to taper (+-) while extruding)
-Revolve (create a "lathed-(round)" solid by rotating a sketch about an axis)
-Sweep (use one sketch as a "profile" and another sketch as a path that the profile folows)
-Loft (create a solid by "connecting" two sketches on separate planes)
-Shell ("hollow out" an object by defining wall thickness, and which surfaces should be erased)
-Fillet / Chamfer (round off or cut off sharp edges on a solid)

Other stuff:
-REAL UNITS!! Have it recognize the abbreviations mm, m, in, ft, ", ', cm... etc and automatically do the calculations to whatever units it acutally uses in the background...) So it doesn't matter whether I type 1in, 1", .0254m, or 25.4mm the line comes out the same.


Of course everything would be completely parametric (defined by numbers) meaning that I could go back and change anything, like changing a dimension on the sketch, and having that change effect the solid that was created from that sketch.


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Postby bruyninc » Thu Nov 27, 2003 9:55 pm

Jim wrote:I was just wondering how possible it would be to add some CAD featues into blender.

I also would welcome the formation of a "CAD group" within Blender!

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Postby thorwil » Fri Nov 28, 2003 2:12 pm

I was thinking about the things knoxer has listed under constraints (making things parallel, horizontaly ...) and dimensioning (defining distances, sizes).
Solidworks uses a collection of concepts to deal with these things on different levels. But it's always better to use only few, rather broad and therfore powerfull concepts. Makes ui design and usage a lot easier!

One could think of some cases of dimensioning to refer to a single object. To define the lenght of a line, you only need the line and no reference.
But we always have the origin (0,0,0) and every point (endpoint, centerpoint) has a relation to it. And a line has 2 endpoints, so its lenght is the distance between them.
That's to show that dimensioning can always be expressed in relations between 2 objects. (Well, I don't know about if this is true when dealing with splines/nurbs, but with splines in 2d sketches in Solidworks you can only use the endpoints for dimensioning ...)

A geometrical constraint like 'horizontal' can be seen as just a property, or as a relation to the reference geometry.

I wonder if Blenders current constrains system could be extended for adressing these things? It would have to deal with bi-directional relations, now it's only uni-directional, far as I know.

Any thoughts on this?

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