Yet another issue with modeling - UGH

I’ve come across another problem with the modeling functions - I think this one is going to raise the importance level (at least for me) to one where it needs to be fixed before the overhaul…It’s making it really difficult to do without being fixed:

When you rotate an import of an STL, the resulting shape is not necessarily centered anymore. This causes problems because you can’t move the imported file once it’s imported…so you are stuck with an out of center shape.

Here is an example:
Import a shape (the default rect is 31x31)

I change the import orientation (to bottom), set the depth (.75) and scale for mm/in (25.4):

At this point, all is good…the object is still centered on the stock
Now…I rotate it (to save lumber) so that it’s straight up and down (in this case, about 127 degrees):

Note now that the shape is no longer centered on the stock.
Centering the outline shows the delta:

Since I don’t want to have to start with 31x31 stock and waste all that wood, I’m creating blanks that are the right size for the resulting geometry (in this case something like 19"x29x5"). If I do that, I’m going to run off the bottom of the piece because the center is lower than the stock center.

This is compounded by the issue (already surfaced) that I can’t center the model on my workspace - because the interface does not allow an imported model to be moved once it’s created. So, I’m stuck having to guess as to how much wood I’m really going to need - and end up wasting a lot of it (and this Honduras Mahogany…and not cheap wood).

Why isn’t rotation maintaining center (like all the other parameters do)? Is there a trick that I can use to force it to stay center? (@WillAdams - that’s a question for you!).

@robgrz Is there any way we can quickly get rotate to maintain center - so I can move forward with this project without throwing away money?

  • Gary

Could it be a function of where the origin is in the STL? Have you tried doing the rotation in a 3D program instead?

Alternately, the Alibre folks have a nifty new program for rotating an STL to make a bas relief:

would that work for your needs? (I tested it a bit, and it’s quite useful for this sort of decorative design)

Wouldn’t the import align the origins? Everything else works…except rotation on angle

I have no idea how to check that…I’m not familiar with other 3D Modeling applications.
This is the file I’m importing:
10.D.stl (150.3 KB)

The reason I need to be able to rotate it - is because there are many of these files (80 of them), some of them are wider than 31"…and exceed the width of my XXL. Since Tiling only works in vertical orientations, I need to rotate the pieces so that they are larger than 31" in a direction I can tile.

OK…I think I figured out a work-around. I can drag the resulting rectangle before committing the import to what I APPROXIMATE as center of the stock. The model moves within it and I can get VERY close to centered by eye. Then I can commit the import. At least I can then save most of the excess stock.

Non-symmetrical shapes don’t have the same center point when rotated. Take an extreme example, an “L” shape…


The center is the midpoint of a bounding box parallel to X & Y in the view.
Rotate it 45° and the center point becomes…


The function isn’t rotation, it’s import. If I were rotating a shape, I’d be fine with what you’re saying…but the function I’m doing is importing a file into a defined space…which implies that I want the object within that space. Everything CC does works to that end…except rotation. Why?

I think because the import is bringing in the shape in it’s saved orientation, and computing the center point based on that orientation. So it is maintaining that same center point when you enter an angle.
What it’s not doing is ‘re-centering’ after the rotation to get a new center point.

What Will pointed out, is that if you want it centered based on the rotation, you need to rotate it before importing it. Which would require a software that can open, rotate & save it in STL format.

Like This… 10.D_rotated.stl (150.3 KB)

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You two are agreeing with each other…but you’re pushing me to another software package to do a basic function that ought to be handled within the import. Remember guys, this is the “paid” portion of the software. Telling me to go to another program, modify an STL that I didn’t create and do not want to take responsibility for (both from a cost and liability perspective), so that it imports correctly is not the answer.

I have a work-around that does not require another product. It’s hokey, but it’s going to work without me having to take the time to learn another software package (this is not a hobby…time matters).

I think we ought to acknowledge that the software has a functional defect (even if mathematically correct) and aim to fix it. Importing an object to be centered within a rectangle should center the object in the rectangle once the import is done. Right?


I don’t think it’s a bug. It’s an inherent part of the software design. It also doesn’t change scale to fit the selected vector or workpiece after you change the angle. The Import image function works the same way, but it doesn’t let you move it at all.

Your shape, if imported to a 31" square scales & fits the model to that vector. If you then change the angle to 127, part of your imported shape now lies outside of the square, as well as off center.

I would think if you are trying to save material, you would want it as close to 2 edges as possible, I would typically use the lower left. So you import it to a vector that will give you the size you want, rotate it, and then move it close to that corner.

It’s a valid request as an enhancement, to be able to manipulate the 3D shape after import. Or perhaps an option to update the scale and/or position after changing the angle…

since I can drag the bounding rectangle before I commit the import, I can do that…that’s the work around that I have found (dragging it and repositioning before accepting).

We can differ in opinion, but saying it’s behaving as designed is not really addressing the purpose of the function .That’s kind of an engineer’s answer :slight_smile: The function is to import into a defined space. Anything that ends up outside of that area is not functionally correct (unless you deliberately scale it).

The whole argument goes away as soon as CC allows the modeling to follow the processing of the geometry creating it. If we had that, we’d center the geometry and the modeling would adapt accordingly. Since there’s a work around, I’m not going to push for any change before we get to the new designed modeling functions…but man is that overdue!!!

At the risk of getting yelled at, Microsoft 3D Builder is free and allows rotation. I have used it in the past for that as well as just plain fixing and STL that wouldn’t open in CC.

Yea, it’s another program and a work around. But maybe easier than the workaround you are using.

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