Bug: Bambu Studio doesn't respect AMS slot choice for identical colors

I have 2 AMS units and loaded generic ABS white in slots A3 and B1, so filament colors 3 and 5 in Bambu Studio. The spool in B1 is nearly empty so I’m doing this as a test of the filament continue feature and in the prepare screen I select change filament and select color 5. All’s good so far.

But when I select print plate and it shows me the filament confirmations instead of B1 it shows A3 as the choice which is NOT what I specified. I change it to B1, start the print and confirm that it actually loads the intended filament.

In theory it shouldn’t matter because it picked the same material/color as what I intended, but in the real world it does matter because I wanted to use up the end of the spool first.

It seems to be a common misconception that the order or numbering of filaments in the studio pallet has something to do with AMS slots - it doesn’t even when you load the pallet by synchronising with the AMS(s).

When you start a print studio tries to match used studio pallet filaments to AMS(s) slots by type and color. I don’t know which it chooses when there is more than one match (probably the first one).

I have never noticed it not match up when I loaded the pallet by synchronising with the AMS(s) - if that’s not guaranteed to be true why the heck not?

While it is a different product, I think the behaviour is the same. With the Mosaic Palette, it chooses the first slot with the requested color/type. And for filament runout, it will only look for a higher slot with the same color/type. So if slot 2 and 3 have the same material, and you force slot 3 to be selected first, it won’t switch to 2 when it runs out.

Did you run the print until B1 was empty? If so, did it switch to A3? I hope the AMS is smarter than the Mosaic Palette.

Yes, when B1 was empty it did switch to A3 and the print completed just fine.

Why should it? The whole concept of synchronising the studio pallet with the AMS is kinda dumb.

If you prepared a job, carefully coloring it with numbers in the studio pallet, and later want to print it again when the AMS might have the required filaments but in different slots what are you supposed to do?

  1. Swap spools around in the AMS to match what you had first time?
  2. Sync studio with the AMS and spend however long it takes to repaint your model with new pallet?
  3. Realise syncing with the AMS(s) is dumb and be happy that studio will at least try to match pallet filaments by type and color to AMS slots when you print the job?

What we really need is for the AMS to handle custom filament profiles. Complete profiles or at least names and checksums to guarantee studio exactly matches AMS slots to its pallet filaments when it can.

Well there are a few issues here. If you have a button that synchronizes BS with what’s in the AMS then that should be an exact match. But I see your point that you really want to know what’s available and not be tied to where it is. The current BS UI that numbers the filaments is therefore deceptive - when things are numbered users think of things in order and that’s where the misunderstanding starts. With no numbers the material/color only should be listed and this should be a set not a list - if you have the same material/color in 2 different slots then they shouldn’t be listed separately in BS, but be available as they are now in the mapping screen for print submission. If you don’t have (in my case) 8 distinct combinations available then don’t list 8 items.

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If they didn’t number (or letter) them the full filament profile name would have to be used in all the menus and dialogs.

Personally I have never prepared jobs by working backwards from what is in the AMS. I add as many filaments as I need to the studio palette and apart from the 1st one being default the order is unimportant. When starting the print studio usually but not always matches AMS slots as desired.

I once in studio changed the color of some black filament to a shade of grey so I could see the preview better. When printing the job studio decided the grey I had set in the AMS for a spool of transparent filament was a closer match and it started printing with that instead of black.

I say again what we really need is custom filament profiles in the AMS.

Your first reply in this post was pointing out this was a common misconception. Numbering the filaments in BS is what causes that misconception.

As a programmer myself (financial applications) I start from the physical reality and model from there, so when I’m starting to think about a multi-color project I load the colors I’ll need into the AMS down in the workshop then go upstairs where I do my design work, sync BS to the AMS and then work from there.

Which means you can’t prepare a job while another one is printing. A pretty major downside for starting from reality. I only have one AMS and the only Bambu filament I have came with the printer. I find the studio AMS sync button to be completely worthless.

On the contrary I prepare jobs all the time when another is printing, I don’t change spools that often. Once I sync to the AMS I don’t have to to it again until I physically change filaments.