Changing diameter of rotary carve when using STL Importer

[mtylerfl]

Now that you mention it, I think I also had to recalculate a new height as well. I will have to go through it again. It can be done without any distortion.

I did something similar with an imported STL egg model I created then imported. I copied/pasted into a new project and played with the height and depth settings quite a bit to be sure it still came out looking like an egg! (I think I had to use a 999 Height if I recall).

I did end up with a 'mysterious' uncarved line around the largest diameter area of the egg, though. It was explained to me that this was caused because I created keepout zones (zero carve regions) that (of course) were even with the top surface of the board. The largest diameter of the egg was shy of the surface by a small amount. Because this was a square blank (i.e., not rounded first), the zero carve region was observed and created that line around the egg's largest diameter which was a tad lower from the surface. This behavior is a deliberate choice because the alternative would have been that the jig would only accept round dowels instead of both square stock AND round stock.

So, when playing with Height and Depth settings to avoid or workout ptn distortion, the screen preview might appear "clean", but it's possible the actual carve might have some unintended raised areas that need to be sanded away. The alternative is to allow the 4.25" default and put up with some air carving.

[bergerud]

I works fine for me but I calculate all the new values.

[mtylerfl]

I works fine for me but I calculate all the new values.

Excellent. Glad it's working!

[mtylerfl]

I did something similar with an imported STL egg model I created then imported. I copied/pasted into a new project and played with the height and depth settings quite a bit to be sure it still came out looking like an egg! (I think I had to use a 999 Height if I recall).

I just checked my rotary "egg project" settings on the egg ptn...I did not change the Height setting. I left it at 100.

[bergerud]

If one wants to create a rotary mpc with a given dowel diameter D (Here comes a little math!) using a rotary pattern output from the stl importer, it can be done. The y of the rotary pattern does not have to be changed. The x length as well as depth and height do need to be changed. The original x length from the importer will be 13.359 (circumference of 4.25 diameter dowel = 4.25 Pi = 13.351). It needs to be changed to the circumference of the new dowel. The depth has to be changed as it will not be as deep in the smaller dowel. When the x length of the pattern is reduced, the height will also reduce. The height needs to be returned to original.

Here is the procedure I have used:

1. Copy the pattern from the mpc that the STL importer created and make note of the depth of the pattern.
2. Start a new rotary project with the dowel diameter you want (lets call it D).
3. Paste the pattern. (It will be too deep and too long but continue.)
4. Change the depth to the new depth = old depth - (4.25 - D)/2. (old depth - 1.125 if D = 2)
5. Uncouple the x y sizes by opening the lock between the edit boxes. Change the x from 13.359 to the new dowel circumference = Pi D. (6.283 if D = 2)
6. Restore the height back to original by changing the 100 to (100)(4.25)/D. (212 if D = 2)

That should do it. The object should appear undistorted on the smaller dowel.

[Bigtyme]

Great information, Dan and Michael. Thank you both for the lessons. I know it will be reviewed many times by fellow CW users....especially me ....

[mtylerfl]

Dan,

Thank you very much for that. Your procedure is extremely useful and helpful to all of us for our rotary projects!

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John,

You are welcome. I'm so glad we have Dan here. He is a math wiz! I don't think there is much he can't figure out.