Preform model orientation always zeroes

Hi there,

I noticed that the model orientation always resets to zero after changing it. As an example, I rotated my part 45°, after touching the orientation tab again, it shows the rotation as zero.

This has worked perfectly with some preform version from last year. But since the problem hasn’t gotten solved since the latest few updates, I have to ask: Is this a bug, or a feature?

I have noticed that too, and it is annoying!

Check out this thread for an discussion of relative vs absolute rotation:

Also, see this discussion back when Preform displayed absolute angles (and gimbal lock led to confusing situations):

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Hi,

Thanks for digging through the forum, I can see why global rotation is turned off. However, maybe the problem could get a better fix.

I often print personalized parts that are identical except for a name imprint for example. After having played around to find the best orientation, I print it and know for sure that this orientation works. Now the problem is that there is no way of finding out the orientation so I can replicate it with the next parts.

Somehow maybe there could be a better solution to this?

Hey @Philipp_Ludewig

Yes, it went from broken to attempting to hide the brokenness. I simply cannot wrap my head around it why it’s apparently so complex or unfixable. ruhro, I can feel that gasket starting to let go… again…

An object is inserted, and lands on the platform. BOINK!

At that point, Preform should say OK, the part is now at zero,zero,zero rotation relative to the global space defined by the build platform - e.g it’s surface defines the XY plane @ zero Z, and perpendicular to this plane defines the positive Z axis. That’s it. That’s the only coordinate system, and it DOES NOT CHANGE! The user should now be able to rotate their parts around any GLOBALLY UNCHANGING axis to orient the part however they want to, and the numbers in the boxes stay exactly as they’ve been set.

Sure, should Preform attempt to use the coordinate system axes embedded in the stl or obj when it imports the part, and drop it in so it’s initially aligned similarly to the active coordinate system in the CAD program at the time it was exported? Absolutely. But that’s where any semblence of local, embedded-in-the-part CAD coordinate system needs to end! Now the part is in the Printer’s coordinate system, which is fixed relative to the platform. All transforms of the part must now be relative to the Printer’s coordinate system.

Can someone @Formlabs please explain why this is not obviously the correct thing to do, or why it’s apparently impossible to do? Would you expect a physical part to somehow retain it’s CAD coordinate system in the real world? If so, should it fall according to it’s CAD Z axis when dropped regardless of the orientation in which you’re holding it? Of course not.

Preform’s environment represents the real world here, therefore objects in it must observe and be governed by it’s coordinate system.

-C

Well, the thing is that a body fixed coordinate system has one painful feature: the final part orientation depends on the order of the axis rotation.

If you rotate something

  1. +90 deg X
  2. +90deg Y
  3. +90deg Z

it points somewhere else than if you rotated it

  1. +90 deg Y
  2. +90deg Z
  3. +90deg X

However, a possible fix for my problem to recreate an orientation is maybe to right click on the part and see ONE possible rotation solution that lead to my current orientation. That way I can replicate the orientation.

Or did I get it wrong here?

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I just posted on this also. This is screwy. Why is it even there if it is made not to work? That’s poor software development.

I can understand for some this might be an issue but for me with the very small items I print Auto Orientation is NOT acceptable at all. yes, fix the X, Y and Z issue but don’t limit the program for all to make a few happy.

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