using C3D for CAD, mechanical design?

R

rosetter

New member
I've been poking around trying to figure out if C3D would work for simple CAD and came to the conclusion it would be easiest to just ask.

I don't need anything fancy, but I do need to be able to model accurately. So functions like easy entry of dimensions when creating primitives, guides, measurement tools, etc. Much of what I do will be destined for 3d printing, so boolean operations that generate sane meshes are also a must.

Any opinions / advice? I realize C3D was not really created for this purpose; would I just end up fighting the UI?

Thanks!
 
I use it for woodworking models all the time. Getting the model into a format for printing out measurement drawings takes other software, but for design and plannng, it rocks. (I have an informal CAD background.) There are several regular posters who are using it for 3D printing.
 
Cheetah is a great visualization tool, I use it to design anything from objects to architectural spaces.

I don't have any experience with 3D printing, but I'm willing to help you with
some testing as this may answer some of my own questions about it.

If you can think of some tests, I'll see if I can carry them out and produce a file you can try printing.
 
Thanks for the replies.

I wasn't really looking for anything specific to 3d printing, and I'm sure it's possible to use C3D to do what I need.
I was more interested in how easy or difficult it is to model with precision.

Most people here don't seem to use it for CAD, but it's easy to imagine that C3D is just fine for the simple tasks I have.

Recently I've been using the much-maligned sketchup, which makes precision modeling very easy for certain applications.
But my next project involves a lot of curves, which is easily outside of SU's happy place.

I guess the best way to find out is just to give it and try.
 
Cheetah, like Blender, Maya, 3dsmax, C4d, Modo et al. is meant for visualisation, animation, product design, matte painting, vfx, whatever. If you need a nice picture or an animation then one of these programs is for you. CAD-Data is often retopologized (built anew) for such circumstances (or at least rendered with a (fake) soft edge (and is sometimes a pain to import). You can create CAD-Models, but those apps aren't meant for that, as often the precision is lacking.

On the other hand there is the whole bunch of CAD modelers, meant for creating and designing mechanical things with precision. As most people here don't really do CAD (I used such apps only a few times myself) we can't tell you how easy it would be to create something made for 3d printing (but at least stl is a CAD format). So some CAD-App would be best for you. As you write your objects will not be very complicated, something like Freecad probably will be best for you (at least for starters): https://www.freecadweb.org

Now, if you want to sell your things and need some pictures for that, then something like Cheetah will be the thing to use.
 
Hi, thanks for the feedback.

I've actually used almost all of those in my day job as a 3d graphics developer.
Modo the most often and with the most cursing (but that's a different rant.)

To use Modo as an example, I could do what I need to but I find the UI quite cumbersome.

Which is why I'm interested in the experiences of people here, if any, using C3D for modeling real world objects with precise constraints.

I looked briefly at the CAD offerings (and also thought freecad might be best for me), but I'm much more at home in the visualization space.
I'm not looking to become a product designer or mechanical engineer anytime soon.

It's my recent experiences with sketchup that have spoiled me.
The UI makes it easy to model with precision.
So I'm wondering how C3D compares. Especially since it could be useful for work and other visualization tasks.
 
Well, with your background I understand your hesitation to use one of the usual CAD programs. I don't feel very much at home myself there. Probably you could do what you need in Cheetah, so why don't you try out the trial and look for yourself what it has to offer? https://www.cheetah3d.com/download.php

For such a use case, though, I could imagine that you'd prefer Sketchup because that's all in all CAD software.

(By the way, taking Modo as an example shows how different our brains are wired. It's my absolute favorite 3d app I ever worked in, especially with the shader tree).
 
Heh.. different, indeed.
I really wanted to like Modo, but I just don't "get" it.
I sympathized with the developers' motivations and welcomed a new dcc tool written from scratch.
I've done training, read docs, watched videos... bleh.
I understand they want to make it "artist friendly", but ...

Funny you mention the shader tree. I can't stand it.

Part of my problem is that the docs were horrendous in every way.
Particularly in explaining the reasoning behind why the UI is the way it is.
"Because it's like photoshop" doesn't help me build a conceptual model of how the shader tree works one bit.

My experience with it is old at this point (I stopped updating years ago) so maybe things have improved. (I hope!)

The other part of my problem is probably just that I'm a developer, not an artist, and hence not the target audience. Sigh.

But wow.. that was quite a digression. :)

And I have downloaded C3D. :)
 
Hi and Welcome.
One of the first things you might miss is units. However, units are always dependent on scaling factors when files are used between multiple programs. This is adjustable in Cheetah3d's preferences. But if you consider a Cheetah3d unit as 1 metre, you can perfectly dimension your objects in SU, for example, as I occasionally do when exporting them as Collada files (scale factor 10.0). See image.
Models imported from SU via Collada (scale factor 0.1) work the same way. The only difference is that Cheetah3d does not understand holes in nGons and does not draw cover surfaces in this case - unless you check "triangulate all surfaces" at SU´s export dialog.
We are here when questions arise.
attachment.php
 
(That's exactly why I mentioned the shader tree. Some people absolutely love it, some can't stand it. And it didn't "improve" (it got enhancements in schematics, but works basically the same since it's conception). The reason was photoshop, something familiar to "digital artists", working with layers, masks and blend modes, only way more complicated because it's 3d. (You could also make an analogy to css, where you can happily overwrite whats below, addressing other parts of the same thing, very versatile, but using it wrong, you can create an absolute mess of something rather simple). I prefer it way over nodes, though).
 
I use Cheetah3D (C3D) for point-of-sale displays (3D printed), furniture, and some light mechanical concepts.
I consider C3D to be quite precise/accurate. Keying in specific dimensions is often my approach. Though, as @frank beckmann mentioned, you will need to mindful of what you want 1 unit to represent ... e.g. 1 meter, or 1 centimeter or 1 foot, etc.
 
I do CAD-like models all the time for work. Mostly sign related construction. Here's an example of one I did earlier this year for a catalog. A lot of the framing I create a spline profile in Illustrator and then import it into C3d for extrusion.

You can see the real product here: https://www.apcosigns.com/alutek.html

I also heavily utilized the McMaster-Carr website for different hardware, as they have a huge library of 3d files (nuts, bolts, screws, etc.). Typically I download an IGES or STEP file from there and convert it to .obj in FreeCAD. https://www.mcmaster.com
 

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Swizl said:
I also heavily utilized the McMaster-Carr website for different hardware, as they have a huge library of 3d files (nuts, bolts, screws, etc.). Typically I download an IGES or STEP file from there and convert it to .obj in FreeCAD. https://www.mcmaster.com
Click to expand...

I'm not very familiar with FreeCAD. Do you typically adjust relative size in FreeCAD before you export to .obj, or is that adjusted within the export operation itself? Thanks.
 
That depends on the the size of the object. For the files from the site Swizl linked to a OBJ import scale factor in Cheetah3d´s Preferences of 0,001-0,002 seems reasonable. Don´t forget Cheetah3d works unit-less.
 
frank beckmann said:
That depends on the the size of the object. For the files from the site Swizl linked to a OBJ import scale factor in Cheetah3d´s Preferences of 0,001-0,002 seems reasonable. Don´t forget Cheetah3d works unit-less.
Click to expand...
Sorry, Frank, I was just asking Swizl about converting the files to .obj in FreeCAD, not C3D. I assume I should do that so they can be opened in C3D, because C3D won't accept STEP files.
 
frank beckmann said:
This is what I did; load the STEP file into FreeCAD and exported to OBJ. Adjusted the import scale to 0,001 and import into Cheetah3d.
Click to expand...
Thanks. I had already completed the export from FreeCAD and import to C3D successfully. I guess I just happened to choose a file to download by random that has some sloppy edges. Not being sure whether that might be related to settings for import/export, I decided to ask. I don't think import/export has anything to do with it, it was just a sloppy file. But while we're here, did you mean "scale to 0.001" rather than "0,001", or am I misunderstanding something?

Now I've gotten sidetracked for a configuration problem with FreeCAD, so I'm reminded of the frustration frequently incurred through the use of open source software. It appears that viewing help for FreeCAD requires a software add-on called "Qt Assistant", and it appears that Qt has closed loopholes that previously allowed the installation of that component without establishing an online account with their organization. Anyway, it makes me appreciate C3D and the valuable resource provided by this forum even more.
 
I don´t have this add-on installed nor do I know what it´s for.
The "reasonable" scale-factor was this one. If the pipes are "1-incher", the factor is still too high.. Pretty sure one can get more precision with a bit mathematics.
And most likely you need to lower the Smooth angle in Cheetah3d.
STEP2OBJ scalefactor.png
 
Cadlet said:
...it appears that Qt has closed loopholes that previously allowed the installation of that component without establishing an online account with their organization. Anyway, it makes me appreciate C3D and the valuable resource provided by this forum even more.
Click to expand...
I still appreciate C3D and this forum more after the experience, but I should probably correct my assertion that installing the "Assistant" for Qt isn't possible without a Qt account. Immediately after I posted the statement, it occurred to me to search my Homebrew installation of qt for "Assistant", and I found it there. All I had to do was make a symlink for it in /Applications/FreeCAD.app/Contents/Resources/bin, and now Help in FreeCAD works as expected.
 
frank beckmann said:
I don´t have this add-on installed nor do I know what it´s for.
The "reasonable" scale-factor was this one. If the pipes are "1-incher", the factor is still too high.. Pretty sure one can get more precision with a bit mathematics.
And most likely you need to lower the Smooth angle in Cheetah3d.
Click to expand...
The add-on is just for viewing help in FreeCAD.app, and that doesn't matter. What's confusing me is the the comma you're using for your import scale setting. What does that do? Why aren't you using a dot instead? How can a comma mean anything in a number that is smaller than 1000? It may be a communication issue, but I'm still confused.
 
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