Functional object in low poly - program and tutorial

Question

I'm losing my mind, it all started out with the idea of a project where I want an abstract shape (I'm going to call it a stretched cube with an angle), now I know a bit of Vectorworks - a 3D/Architecture drawing program. I found nothing in all the tutorials how to make something low poly but still be able to for example screw the bottom of with a thread for example.

I found numerous shapes I like on Thingiverse but they are all STL files which I've learned so far are hard to edit and make them functionally usable when cross transferring them for one to another program.

Today I gave it another try to find other programs which can give me the result and functionality I want. Thus far I've only found program where you make the shape perfectly and then by using a mesh program like 123make and Meshmixer to then change the outcome of the rendering. But in my case this makes some parts unable to use anymore as example the threading?

So for the question I their a program which I can make a low poly shape (example below) where I still can add holes and threading like you can do with AutoCAD, Vectorworks.

I hope somebody knows how to do this I've been searching and asking around for weeks!!

This is an example of the type of shape I would like to create, Low poly vase - mine would be exactly the same but it would be to give you an idea

Example of the thread I would like to implement in the shape above, Tap and Die for 3D printed threads

Answer 1

Yes, you can accomplish threading easily with something like 3Ds Max, Blender, Maya etc. I use Maya personally so, in Maya, all you have to do is:

1. Create a cylinder. This will be the main body of your 'screw'.
2. To make the thread, you need to create a helix primitive. You can edit the number of coils and the coil thickness in the Maya GUI.
3. Once you have the thread, it is a simple matter of performing a couple of boolean operations. The first boolean (union) operation will unite the screw made in step 1 with the thread made in step 2. The second boolean (subtract) operation will cut out the thread from the object within which you want your screw to be driven into. When you print the two models, you should find that the screw nicely turns into the object from which you cut out the thread.

The point is: yes, it is easy to do such things in most 3D software packages. Maya comes with a nice selection of default objects you can use, so essentially you need to do no 'modeling' yourself to create something like the example you showed us.

Your next question, about editing models on Thingiverse. The reason why you cannot edit them easily is because most models there have been decimated and triangulated, which makes them very difficult to reshape or edit because the topology is no longer strictly manifold -- it is just a big mess of triangles!

If you want to edit Thingiverse models, I recommend something like ZBrush. You can import triangulated models and then rebuild the geometry into quads (using DynaMesh, for example), which you can then edit to your liking. Once done, you can simply decimate and re-export as STL or whatever extension you need.

Finally, low/high poly is not so relevant in 3D print outs, especially in mechanically functioning parts. This is because most models are created in high resolution (high polygon count) and then decimated + triangulated down to truncate file sizes. But the functionality and physical feel of the model should not change due to this process - it just takes practice and lots of experimentation.

Hope this helps :)

Hassan

Answer 2

I've had my share of struggles with the issues you're having - bridging the software gap between hard-edge, parametric modeling tools (typically CAD) and more free-form, 'soft'/organic, modeling tools. It's not a trivial task to work across both domains simultaneously.

The simplest workflow I've developed is:

1. Create a simple CAD model of parts of the object you're trying to make that have mechanical/precision features (e.g. threaded screw holes, joints) in a CAD program (e.g. AutoCAD, Inventor, Solidworks, Fusion 360).
2. Export a high-precision STL of those parts
3. Create/generate the 'soft'/organic portions of the model in your software suite of choice (e.g. Blender, Maya)
4. Export an OBJ file (or STL, if the option is available) of the 'soft' parts
5. Import both sets of parts into Meshmixer and combine them there.
6. Export to a single, combined STL
7. (Optional) Pass the 'end product' STL through a model "fixer" - I quite like the Microsoft Model Repair Service

Meshmixer is a powerful but poorly documented tool. In my experience, it's capable of accomplishing most of the basic "fixes" most models need in preparation for 3d-printing. It is possible to do some amount of sculpting/organic modeling within Meshmixer itself but you'll probably find it inferior in that regard to other software suites, if you know how to use them.

Answer 3

If you have some programming background, take a look at OpenScad. It allows you to model using a functional programming language. Basically all of the customizer models on Thingiverse are written in openscad. My gut says you can use the poly command to string together a bunch of polygons to do what you want.