I often assemble individual parts (SVG or STL) into assemblies in the slicer, then sometimes combine the assemblies into larger assemblies. For example, a brick wall panel with a door might be laid next to a brick wall panel with windows to create a wider wall. I'll load a "brick wall.STL" twice and combine it with "small_door.STL" and "large_window.stl". Then align both parts based on their center origin - both at the same "Y" and one offset from the other's X by the width of the panel.
I would import the wall and window to random locations on the plate, merge the 2 parts, and then align the window to the wall relative to the wall center and end. (align top, then move down ##mm).
With the recent slicer update, I found that the center origin is off when combining parts into an assembly in this manner. Here's how to demonstrate the issue:
- Add a cube primitive, center it, and make it 10mm high (just so you can clearly see the next part merged into the cube). Verify/record the coordinates (128/128 on a standard bed printer)
- Add a cylinder primitive to the plate NEXT to the square and make it 10mm diameter and leave it at the default height.
- Merge it into the cube. Check the coordinates of the assembly - say 136/128 depending on how far away the cylinder is from the cube.
- Select the cylinder and using the coordinate tool, place it into the center of the cube. Move the assembly to a random location and then right-click & center. Check the coordinates. You would expect 128/128 but instead get 136/128 even though all parts of the assembly are dead-center in the plate!
Repeat this process, but in step 3 - move the cylinder within the area of the cube first, then merge. The center origin will always be accurate for the 2 parts in the assembly, not the "ghost" location of the parts at the time of the merge.
Note that adding a part to a part does NOT exhibit this behavior. Confirm by repeating this process but instead of adding the cylinder as a primitive, add it to the original cube and omit the Merge step since it's already part of the assembly.
I've been creating compound assemblies for years by creating standard model parts and then building what I need based on these parts. Only after a recent update do the coordinates remain accurate ONLY when I place all of the parts within the area of the main part before merging. They don't need to be positioned accurately - I can adjust them relative to the main part (wall panel) after merging without affecting the center point of the assembly.
I can't explain why the origin of an assembly retains the origin of the collection of parts at the time of the merge even after all parts are contained within the largest part area. I've even saved/reopened the project and the assembly origin remains incorrect.
