BRL-CAD provides several ways to model 3D geometry including a graphical tool named mged, another named archer, and various ways to create geometry using scripts. We use 3D models for development and to showcase our features. You can learn the basics of 3D modeling in just an hour or two.
This task involves modeling a gerotor. This is basically a cool pump. Your job is to model it natively using any of BRL-CAD's tools (i.e., don't model it in something else and import) using 3D primitives and Boolean operations (i.e., without using 2D sketch entities or polygons).
The gear set should be accurately modeled in such a way that it can be printed using a 3D printer. This means that the model should have regions defined for each part and no overlaps (use rtcheck and/or gqa commands to verify). Create one top-level combination to group everything together.
References:- http://en.wikipedia.org/wiki/Gerotor
- http://www.pumpschool.com/principles/gerotor.asp
- https://www.youtube.com/watch?v=nodDVMl-nLA
- Introduction to MGED at http://brlcad.org/wiki/Documentation
- Submit your model as a .g file (BRL-CAD's geometry file format) and a rendered PNG image. You can run "rt -s1024 -o your_rendering.png your_geometry.g your_top_level_object" to create a PNG rendering of your model.
| File name/URL | File size | Date submitted | |
|---|---|---|---|
| gerotor.jpg | 41.2 KB | December 28 2014 14:06 UTC | |
| gerotor1 | 6.2 KB | December 28 2014 14:06 UTC | |
| gerotor.tar.gz | 7.8 MB | December 31 2014 20:26 UTC | |
| gerotor.tar.gz | 7.8 MB | January 01 2015 19:06 UTC |
I would like to work on this task.
This task has been assigned to Aditya Gulati. You have 100 hours to complete this task, good luck!
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Aditya, this looks like the right idea, but doesn't look like it's actually correct. That is, it looks like a gerotor, but it doesn't look like you made a model that will actually rotate correctly. A gerotor inner gear must maintain tangency with the outer gear and the rotation of the inner gear should result in a stable rotation of the outer gear.
Moreover, I would have expected a 3-prong triangle gear to look more like this: US07147445-20061212-D00002.png
That's not to say that a pointy gear cannot work, though, so please just cite a source or example that indicates one will work that way. See the youtube link in the task description for details on how you can calculate an exact construction for a 3-prong gear.
One of the mentors has sent this task back for more work. Talk to the mentor(s) assigned to this task to satisfy the requirements needed to complete this task, submit your work again and mark the task as complete once you re-submit your work.
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I would like to work on this task.
This task has been assigned to Andromeda Galaxy. You have 100 hours to complete this task, good luck!
The work on this task is ready to be reviewed.
It needs a shaft to work.
Do you have an idea where the intake and exhaust are?
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Shouldn't be the rotation axis hole round? And how about modelling the shaft too?
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I tried modeling the shaft as well, but that blocked too much of the geometry of the pump.
My thinking with the shaft was that the pump assembly could just be dropped onto any rotating shaft as part of another larger assembly, so making the hole square makes sense in order to make energy transfer from the (not bonded to the pump) shaft more efficient.
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