Warning: Old material could not be removed from the document, possibly because it is the default material.

[ltomuta]

The STEP files I receive from customers are, for the most part, defaulting to Steel as the physical material. When I try to change it to something else, I get random results. Sometimes it works, other times it fails with the above warning because apparently in this context default means something else than "implicit selection in case nothing else is specified".

The only thing guaranteed to work: deleting part's "default" material, which gets replaced instantly with Fusion's default, which in my case is Aluminium. 

I don't understand how a bug/limitation for something this basic is allowed to persist for so long in the product. Especially now that in the Manufacturing workspace they are actually taking the material into consideration for selecting e.g. feeds and speeds. So it should be easy to set the material as part of the workflow. But it is not.

[CGBenner]

@ltomuta 

Hi, would it be possible to share one of the STEP files where you ran into this problem so others ca take a look and maybe find some suggestions?  Maybe it has something to do with how the STEP was created at the source?  Thank you!

[ltomuta]

test_material.f3d is a simple native Fusion design. The material applied is my configured default, Aluminium 5083.
test_material_steel.step is a version of the same file after the material was successfully changed to Steel.

When you import this step file, there is already a problem as there are two Steel materials listed where there should be one.

Say I want to change the material to Brass. Which of these materials I should drag and drop the new material onto? If I drop Brass onto the first Steel material on the list, instead of having it replaced I get Brass added to the list of materials and the warning message is displayed. The expected result is that the old material is replaced in the list with the new one and my component has only one material as only one is in fact used/needed. The warning also makes no sense from a default perspective. My default is Aluminium 5083 if anything, and there should be no trace of that material left in this imported step file.

eMG1-110-G4.stp is a random sample step file found by way of google search. There does not seem to be a material specified in it but upon opening it in Fusion "Steel" is listed as the material in use. Why Steel and not my default material? If I try to change the material by dropping e.g. Copper onto it, I get the same result: Steel remains in the list, Copper is added to the list of materials and the waring is show.

If I try to delete the added Copper, I get my default Aluminium added to the list (for no reason)

[ltomuta]

--- deleted out of order e-mail reply ---

The only thing worth keeping from it is the observation that I may have uploaded a STEP but by the time I work on it and save it that's a native F3D file so this is exclusively a Fusion problem.

[CGBenner]

@ltomuta 

Were you able to get any resolution on this?  One thing I did not ask earlier is:  Where are these Step files coming from?  A variety of different software, or are they all from one system?  I wonder if, at the source, there is a way for the person preparing the Step for you to remove the material before exporting it?

[ltomuta]

Nope, no progress. As you can see above you can repro the problem by simply exporting a simple native F3D as STEP and then importing it back so the source is not that relevant (our various customers use various software packages).

[CGBenner]

@ltomuta 

I'm going to move this to the Fusion Support forum and tag @RajkumarIlanchelian to see if he can offer some ideas.

[Phil.E]

Hi,

Thanks for posting about this.

The error dialog refers to the default material, and while it looks like you may have found other bugs here, the basic message of the dialog is correct. The default material cannot be deleted in a parametric model.

There was a change to Fusion that put all imported designs into a default state that is the same as your preferred document default. People were complaining that they would open a step file and do work on it before realizing there was no timeline. At any rate, the step files you open have timelines and that interferes with deleting materials, and it always has - this is not new, and it is why that warning message exists to inform you of this.

I found a couple bugs, and you helped point them out, about how default materials get mixed up, e.g. steel vs aluminum as the default. I found the same thing when I set mine to Aluminum and tested it. I'll follow up with the materials developers to see what they can do about this.

To use whatever material you like, turn off the timeline. Here's a video about it.

[ltomuta]

Hi @Phil.E 

Yes, I know that the timeline is now finally on for imported files. For me it was always on, I had a an add-in that was enforcing this preference when Fusion was ignoring it. So this always annoyed me. Still, the very notion of a default material does not make sense. What is a default anything for an imported STEP?

Timeline wise the "default" (or rather initial) values are(?) captured in the "Base Feature1" entry. Anything past that should be fair game so once I make an edit and change kryptonite into chalk, any trace of kryptonite should be gone. I don't care that this was kryptonite before. It should be what I need it to be and only that.

Is it worth making a timeline entry to mark the change? Maybe. Is it worth annoying me with a warning and keeping confusing material duplicates around? Nope.
 
Thanks for reporting the other related bugs.