Confusion around object colours (solution in discussion)

Bambu Lab Software Bambu Studio
1

I think I’ve found a bug in the multi colour printing by object. However, maybe I’ve screwed up a setting, but I can’t see how.

Background: I have a model, from Fusion 360, with multiple objects printed in different colours. If I use a previously created .3mf file it works perfectly. If I export a new model from Fusion I get this problem, despite the model not having changed (or even been re-saved) in Fusion. You’ll see why I see this as a BS problem, not Fusion.

I’ve managed to greatly simplify the problem to illustrate what’s happening.

I’ve uploaded a screen capture video that shows this in action, but here are the steps.

Video: https://natatorphotography.com.au/misc/bambu/paint.mp4

I export a very simple model as a .3mf. One object is a block, the other a disk. They are not connected.

In BS I change the colour of the disc, using the objects tab.

In the objects tab it shows the object as being the new colour …. but on the plate the colour still shows as the original. I think this is the first indication of a bug.

So, with that object still set to the new colour, but showing the original …

Go into the paint bucket tool. Repaint to a third colour (as this makes it clearer). Object now correctly shows the painted colour. In the objects tab, it still shows the colour I set it to there, which I believe is the correct behaviour as the object has only been painted over.

Go back in, erase the painting ….. object now shows as the correct colour on both the plate and objects tab.

Doing that last step also works as a workaround for this problem.

So, you need to paint something, then erase it, and the colours come right.

Additional: My original model had lots of objects I was trying to colour and none of them would change. However, I only had to do the paint/erase-paint on one of those objects and the colours came right for them all.

A bug? I think so, but maybe it’s an obscure setting I’ve changed and it’s me.

It’s only just started happening for me but it does happen consistently. This is BS on a Mac, latest OS, and I assume it is a rare set of circumstances I have as obviously it isn’t happening for others. Happy to do any testing if people have ideas.

Thoughts?

1 Like
2

This is (surprisingly) a feature.

If any model or part is painted, you cannot set the filament of it to a colour using the numeric keypad or menu options.

The reason is; if you (or on your behalf) something is painted, that is deemed to be your choice and accidentally changing (as noted above) will not change that priority.

The solution is to erase the painting on any particular modems or parts and then it removes the priority and you may choose the correct filament choice.

I noted at the top it is surprising, not because it a bug, but rather the user experiences this due to actions performed outside of the slicer and may nit appreciate the process.

Keep in mind, if you import something with colour and that colour has been added partially (as in, not as a single solid colour applying to the whole part or model, even if the whole part is the same colour), it is deemed to be the users choice and it is respected.

It isn’t rare as it is often asked on the forum, I have replied to a few myself.

It is worth noting you can tell which parts or models have been painted by looking on the right side of each part/model in the objects list and look for the paint icon. If it is there, BS uses the paint information and note any filament changes unless you remove the painted choice first.

1 Like
3

Thanks Malc but, and this is to help clarify it for me, a couple of things …

  1. You said “If any model or part is painted…” I hadn’t done any painting on the model at all. The video starts immediately after the import.

1a) Just tested and if, immediately after the import if I do go into the paint tool and “Erase all painting” then I can colour the objects correctly. It’s as if BS thinks the model has been painted but I haven’t actually done so.

  1. This behavious is new (though I’ve been offline a month or so). Previously, when I’ve imported the same models this now happens with I only had to change the colours in the objects tab. I never had to do this “erase all painting” step.

Also, in case it is relevant … The model in Fusion was as simple as it can be. I didn’t go and change and colours, materials, or whatever in Fusion.

More of your thoughts please. :slight_smile:

4

Hi, which Studio version are you using?

.3mf import handling changed in v2.5, especially (or maybe mostly) around color assignment, as per the release notes.

Are you getting the color assignment dialog on import?

When I import .3MF files made with Fusion into Studio v2.5.0.66 I do get the color assignment dialog, even though I didn’t explicitly assign any appearance/material to the objects in Fusion. (Fusion does have a default appearance/material option, though I’m not sure if that needs to be enabled somewhere explicitly.)

If I hit OK in that dialog, then I can re-create the issue you’re describing. What happens is Studio surface-paints the object/part(s) (mine shows the painted icon next to each object). So, to get Studio to use an actual assign filament for the whole object/part, the painting has to first be removed manually.

However if I Cancel the color assignment dialog, nothing gets painted. After that I can manually assign filaments to the imported objects and the colors are correctly reflected in the Prepare tab preview right away.

That is also how Studio v2.4.0.70 behaves, since it doesn’t try to apply surface paint to objects.

Also possibly relevant: Solid body colors replaced by surface painting. Please let us turn this off!

HTH,
-Max

1 Like
5
  1. You did, at least the file you imported had been thus the on your behalf reference.

Here also.

Your video doesn’t show what happened in the CAD package, only the file having already been imported.

  1. It isn’t new in my experience, but I do nit have your workflow.

I do not know if this is a Fusion thing that changed or how BS interprets something now that a fusion has done for a while.

You have the option to import the geometry during import, this brings in the model data without any extra information.

Based on the release notes it appears to be the latter of 2.

how BS interprets something now that a fusion has done for a while.

1 Like
6

Hi Max

Yes! I hadn’t clicked that. Yes, this “issue” has only started since the colour assignment box appeared.

I’ve got exactly the same as you there, and if I hit cancel, which I hadn’t before, the behaviour is as it used to be and I don’t need that step of erasing the painting.

I now understand why it’s happening and it isn’t a bug (just a weird way of doing it in my opinion) and is very easy to work around.

thanks!

1 Like
7

Hi again Malc :slight_smile:

I think Fusion hasn’t changed but, as Max explained, it’s just a new behaviour in BS, which by hitting “cancel” during the new colour assign dialog during the import is easily circumvented.

That’s a useful tip though on the geometry thing, hadn’t considered that.

:slight_smile:

8

I assume you meant Malc.

I know, I wrote that in the previous response.

My points about why paint does what it does, how it is a feature, how to remove it, the order of priority and why it correctly assumes anything painted was a choice all stand.

1 Like