To get a feeling on how spur gear teeth get their particular shape, I created a short visualizer:
The whole process of emulating the action of the cutter on the rotating blank was done in Blender, this time not using a add-on for once, but a simple script that runs from the text editor.
The script renders a frame, then applies the boolean difference modifier that the spur gear object (the 'blank') has, moves both the blank and the cutter and adds again a boolean modifier and repeats this as many times as desired.
I am not yet sure if I will write a small article explaining the code, it isn´t all that complicated, but in the meanwhile you can download the .blend file from my GitHub repository (click on the 'download raw file' icon in the upper right corner to download).
I have been experimenting a bit with geometry nodes lately and I thought I´d share this one
The .blend file is available from my GitHub repository. (Click the 'download raw file' button in the upper right corner to download it; Inside is a sample scene, and the geometry node itself is called 'Hexagon pattern')
Tips
The input mesh is simply repeated across the pattern and nothing fancy is done to it. If the repeated meshes are butted up to each other you may want to remove any coinciding vertices, and I could have done that in the geometry nodes itself but that is unnecessary as you can easily apply a weld modifier to achieve the exact same effect. And other modifier too of course, like a solidify modifier perhaps, to give the grid some thickness.
If you just want a quick hexagonal pattern in a shader, you may want to have a look at this post.
Some details
The node setup is pretty straight forward:
We get the bounding box of the object we want to repeat, scale it a bit so we can add a gap if we like, and the repeat the mesh for a set number of iterations along the x-axis. Then we replicate the result along the y-direction and end with applying a material index.
If we look at the repeat x section, we see that there isn´t much to it:
We simply join a shifted version of the input for a set number of times. The offset in the x-direction is twice the maximum of x dimension of the bounding box, i.e. we assume that the input mesh is symmetrical around the origin.
The repeat y section isn´t all that much different, except for a little detail:
That detail is that we move the new mesh up in the y-direction by a configurable scaling factor, where the default is fit for a six sided cylinder, a.k.a. a hexagon, but you can change that to something else if needed.
We also move the row either to the right or the left, depending on whether we are in an odd or even row. We determine this odd/evenness by taking the iteration number module 2 and using a switch node to provide a multiplication factor of -1 or 1 respectively that we apply to our x offset. If we wouldn´t alternate this move in the x-direction we would get a skewed grid, which might be find, but I prefer to work with a square grid.
I'm interested in more than just Blender 😀 so I started a new blog. It might interest some readers of this blog as well as it has a bit of a mathematical focus, just like quite a few articles here.
It is all about assumptions and questions that may pop up in everyday life and that may be solved with a bit of thinking and pen and paper, hence the title "On the back of an envelope".
Focus is on doing our own research up, backed up by proper references to articles by real people, and no easy AI slop.
In this module we will refactor the render_done add-on encountered in the previous module
into a multi-file add-on.
The first video will take a look at why splitting up an add-on might be beneficial for
maintenance, reuse and the options to include non-Python files, something we will make use of
in the second video where we will add a custom icon to one of the operators.
