Sizing gears imported as .dxf files

In preparation for carving a series of student designed gears for one 4’ by 8’ panel of our “gear wall” at our facility (the Saint Louis Science Center), we use Gearify as a design program which exports the designs as .dxf files. When importing gear files into Easel, how do we make sure that each of the gears will be carved at the same scale (for example, at so many “inches per tooth” as noted in Inventables’ Gear Generator)? BTW, we use Gearify because it allows us to design non-circular shaped gears.

We need to be able to take designs produced over a series of weeks by the students, import them into Easel as they are produced as .dwf files, and then carve them, one or two at a time, all to the same scale. If we were doing this in the Easel gear generator app, we would just have to make sure that the “inches per tooth” value was always set to the same number.

I’m not sure what to tell you. It sounds as though you want Gearify gears to be able to mesh with Easel designed gears.

One thing you might try is to create a project here and drop some Easel designed gears in it and also some Gearify .DXFs in the same project space. Then make that public and some of the forum members can give it a look.

If you’re up for it, I’m St. Louis and could pop by the Science Center to get a better sense of your challenge.

If you take measurements before importing and after, wouldn’t this give you a feeling for the right size? In Easel, make a circle of the size you measured in Gearify and place it on top to see if they match.

After reading the Gearify documentation, it looks like this package is mostly used for designing non circular gears. Those won’t mesh with circular gears designed by Easel. Also, one student’s non circular gears won’t mesh with another’s even with the same tooth profile unless the students both base their designs on compatible functions.

If the gears can’t mesh student to student, it would seem that compatible tooth profiles wouldn’t be a priority.

That said, if you would like for everything to rotate as a long gear train, you might consider stacked gears. The student’s exotic gear would be concentric with and above a standard circular gear, the exotic gears would then all mesh down the chain to the last one which would be in front of and concentric with another standard gear. That gear would then link to a similar arrangement for the next student’s gear train.

This project is just Gearify gears, but they will be carved on an Easel driven X-Carve machine.

This is my plan: After I design my first gear pair in Gearify, I import them into Easel and they are tiny (each is less than an inch in diameter). How to I scale them up to, say, approximately 8 inches in diameter, so that the next pair I produce (the first gear of the second pair being able to mesh with the second gear of the first pair) is at the same “scale” as the first pair?

Does this make sense?

In a world of scalable vector graphics, how does one set a scale for a project so that everything is designed/built to that same scale? A very noob question, I know, but…

Instead of using compatible functions to get a mesh, we plan to create a chain as follows:

  1. design gear #1
  2. base shape of gear #2 on the shape of gear#1
  3. base gear #3 on gear #2
  4. base gear #4 on gear #3
  5. et cetera

Gearify works by designing a first gear (the “known” gear) and then using that first gear’s shape to craft the next gear (the “conjugate” gear).

I like the circle idea, Luc, and I’ll try it today and report back.

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@BillStanard Can you share a dxf or two here? Along with any known dimensions.

The scale of these two gears (each as a separate file) are as follows
and the .dxf files are here attached.conjugateGear.4631.maxRadius.dxf (38.6 KB)
knownGear.5067.maxRadius.dxf (37.1 KB)

As far as the “known dimensions,” I guess I’m not sure what that really means. The dimensions in the screen shot above are in what units? Because we are in the world of scalable vector graphics, how do I assign units (as my physics and math teachers always told me to)?

So, I would take your 0.506655 Known Gear Max Radius to be in millimeters because that is the way it is being treated as it is imported into Easel when set to mm. The DXF file as generated by Gearify does not include a $MEASUREMENT parameter which would tell the program reading the DXF file whether the units are metric or imperial.

It looks to me as through you are going to have to work on your Gearify end to produce gears of the size you want. Easel is doing a fine job of importing your tiny gears.

There does not seem to be a way in Easel to specify a numerically entered scaling factor. You might be able to import your DXF into another piece of software and scale it that way.

Again, I would look at the Gearify software to see if you can’t set a scale somewhere in there so that you directly produce gear designs of the desired size.

Reading through the Gearify manual some more I would recommend the following.

If you are using the free hand create using spokes, try zooming way out and then adjusting the spokes. I think this may help you with size.

Also, there is a template feature where you can import an image and work with that to try to create a gear similar to the image. If you import art of a known size for the template, this might also get you into the size range where you want to be.

Finally, if nothing else works, export your gear not as a DXF but as a CSV. Then import the CSV into excel, multiply the numbers by some scaling factor and then save a CSV back out. You can then reload the CSV back into Gearify and continue working or export it from there as a DXF.

This is how I would do it, but without some sort of standard set in generating you won’t get a set of meshing gears.

You can create all of your meshing pieces in Gearify and export their DXFs. Then load all of the DXFs one by one into one Easel project. Select all and manually scale. They will all scale together and will all still mesh. You can then adjust the layout and cut them out together, or you can make copies and delete the unwanted pieces so that you can do them individually.

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@HarryC.Ragland I’m just saying that without giving some parameters (I’m not familiar with gearify) to the several students designing the gears, one set of gears won’t mesh with another. I may of missed it, but if each student is designing a pair of gears that is acting independently of the other pairs, you can just scale to an appropriate size and go. I was picturing a wall of gears that all rotate with one input. That, I think after looking at gearify, will be difficult with students.

Harry’s first sentence (“So, I would take your 0.506655 Known Gear Max Radius to be in millimeters because that is the way it is being treated as it is imported into Easel when set to mm.”) tells me what I need to know and helps me get my head around the idea of drawings without units. Thanks, Harry!

This “standard in generating” is what I am trying to achieve. That way I can accept inputs from multiple designers for a common project. Thanks, Neil.

This is perfect! In trying to create a work flow for the project, this is just the advice I needed.

This is exactly what we are trying to create. With Harry’s advice to import all designs [in which gear one will be the father (sorry, mom!) to gear two, gear two the father to gear three, gear three the father of gear four, et cetera…] and then scale all of them at once, we will achieve the desired result. I’ll try it with my kids today and report back.

I tried this using your two gears from the other day and my suggestion does work. However, there is a small problem. The outside of the gear and the gear’s center are not grouped as one piece. You can scale everything up just fine but all of the gears and centers are stacked on top of one another. You can then select a gear and a center (hopefully the ones that are paired together) and move them. This process will get very messy if you have more than 2 gears.

I don’t see an obvious way in Easel to group objects.

@BillStanard I’d recommend using Inkscape as the intermediate step. You can decide on a multiplier you want to use when importing dxf files and you can manage grouping easily. From there, save the svg and open in easel.
Please update this thread with your progress…I may have to buy gearify and try this with my students.

Will there actually be any design/uniqueness if done this way? Again, not familiar with gearify, but it seems to me that the shape of the daughter gear is predetermined by the shape of the mother gear.