Fusion keeps changing my WCS

[eerier_bleach0f]

If I simply flip the direction of an axis Fusion very intelligently and intuitively just moves my WCS.............

I hit "flip" because I wanted to flip it. If I wanted to move it I'd move it....

Stop doing that. I already selected a WCS point. Stop moving it...

[programming2C78B]

Must be a mac thing, doesn't happen over here. 

[eerier_bleach0f]

@seth.madore Is this a "Mac" bug or a "Me" bug that I've noticed on 2 different expensive rMBPs?

[seth.madore]

It is not a "you" bug or technically a bug at all, it's just unique design choices that were made many years ago. The workflow is intended to be left to right and top to bottom. If you establish your WCS point first and then create your alignment, all bets are off. This behavior exists on Mac and PC alike.

-EDIT-

I'll allow that this "could" be a regression, but near as I can recall, this behavior has always existed.

[brekmiller]

Hey Seth, maybe we should take a closer look at this.  I remember back in 2020 we had CAM-22201 which fixed an issue like this when the WCS origin was based on a stock box point.  In the video, it looks like WCS origin is set to model box point.  So this might be different issue.  But it does look like the behavior doesn't match the description in CAM-22201 of what the expected behavior is supposed to be.

Can we get the f3d file for this?  I would like to see what happens if we change the WCS origin to stock box point.  Also, changing the WCS orientation so that it's 45 degrees out from the axes of the view cube made it more obvious what was happening.

[seth.madore]

It's easily reproduced in any file. I'll open a new ticket

[seth.madore · Accepted solution]

I've logged CAM-54813 to investigate this issue

[brekmiller]

Thanks for opening a ticket.  I tried, but couldn't reproduce it in an example I have.

[brekmiller]

The OP's video shows the origin moving when "Flip Z Axis" or "Flip X Axis" is clicked.  In Seth's video, the origin doesn't move when the flip boxes are toggled.  This is what CAM-22201 fixed.

Seth, your video shows you changing the Z axis and X axis selections.  This is different.  The "box points" are the corners and centers of the bounding box of the model.  However, there is no single bounding box.  It depends on which directions your x-, y-, and z-axes are in.  So when you change the z-axis or x-axis, Fusion needs to calculate a new bounding box.

It might still be that Fusion should, after calculating the new bounding box, try to find the box point that is closest to the old box point.  I think that is what the algorithm does when you click the flip buttons.

It is more obvious that the bounding boxes are different if you choose a new z-axis that is 45 degrees different to the old z-axis.  The WCS origin has to move because the new box points don't match the old box points.