Disconnect between Prepare and Slicing

I’m a casual user, original rationale for the printer dissolved but I like it. Yesterday I created a model with two colors (think coaster) in Fusion, exported as 3MF and Step (same result with each).

I’ve only used Bambu Studio and have not had a problem until now.

Prime Tower is enabled and shows in the two colors in the “Prepare” screen.

In the “Preview” screen it only shows one filament color, one filament change time and not the secondary color. Print time seems right for only one color and no filament change. Prime tower isn’t shown.

No error messages after slicing.

Both filaments are PLA.

X1C, 0.4 nozzle, 0.12 quality

Any suggestions?

Tricky to say without screenshots. If your second color is supposed to print very fine lines (such as small text), you may need to slice for a .2 nozzle, use the “Arachne” wall generator, or even both.
Or it could be something else entirely…

These aren’t dainty. Diameter is 0.8". I tried the your suggestion for wall type and it didn’t make any difference. I actually printed them yesterday evening but they were too thin so I went back into Fusion and made them thicker.

The second color is lost and it shows only 1 filament change even though it is set to print by layer

Thanks, that helps. It appears that Arachne should enable printing if line width would be an issue.

How about thickness of the 2 parts? Is the orange part below a layer height?

Finally, did you merge the objects into an assembly (select both, right click, “merge”)?

The only option was to separate.
I deleted 3 of them. Selected the remaining one and then I could merge.
It is still the single color after slicing.
I need to leave and do some other work that I am competent at. Don’t hesitate to give me some more thoughts.

Show a screenshot of the settings sidebar with “process” switched to “objects”
Even better post your 3mf project