Fusion 360 - unassign and delete physical material not working

[Anonymous]

when i go to unassign and delete a physical material from the physical materials panel, it just stays there. In this case I initially had my object set to white ABS plastic, then I put a brass material onto the object. Being OCD I want to delete the abs material out of the panel but when I go to do that, nothing happens. Is this a bug?

[mqltd]

Use Components within an assembly. You can quickly change material for Assembly then every new component has the assembly default material. You can still edit individual component material at any time.

[mqltd]

Shows how material properties work in assemblies

[mqltd]

See recording

[powerflexplacement]

I'm sorry, but I'm with the guys above on this. It's absolutely infuriating that you can't delete a material that isn't required from the part. If this is the case, either this needs sorting, or the assign and delete button needs removing from the material that you can't delete. As you've said, there's a work around for this, but that shouldn't be the case. There shouldn't need to be a work around for something so simple. I hope Autodesk realises this and sorts it out in a future update.

[abantu]

it s january 2024 - and i also have the same issue

i made a design (sorry can t share it because it s under dna) - and my preferences are default 'steel' - but for some parts i applied aluminium as physical material

my client asks for the weight of the structure and i get a huge weight - when i go through the different parts i see that the aluminium parts are set in the design properties as 'steel' (??) - but in the parts design as aluminium AND steel - and i cannot take away the steel !!

the weight of my structure is entirely calculated as 'steel' (190kg instead of the expected 140kg !!!!) and thus entirely faulty...

i now wonder (don t have time to check that) if the same physical materials (steel) are used for simulation instead of aluminium ??

[Phil.E]

Happy New Year to you too!

I saw your questions and wanted to post to clear up some of what appears to be confusion about how physical materials affect designs.

The presence of a material on the physical material "in this design" list does not affect the model.

Here I have 5 materials "in this design". 

But if I check the properties of the body, there is only one material applied to it.

So just to clear up any remaining confusion you might have:

Assign a physical material (video)

How to find the weight, mass, volume of a part in Fusion (web page)

Let me know if you have any other questions.

[abantu]

hi @Phil.E 

tnx for taking time to respond !

there is no mistake in understanding - i can show you three screenshots that are part of my design

as you can see - i have one seperately designed body part that should be aluminium but that has been designed in steel (because that s the default material) - i change it in the preferences of the body itself : physical material -> 'aluminium' - but the icon of the steel material stays in the physicial material dialog box and i can even 'unasign and delete' it but that function doesn t work ?!  - the steel icon stays on top and because in the properties the body is still 'steel' although i changed it to aluminium

here is a link to a cut of the part - https://a360.co/3NTTh9O

i have tried to reproduce the issue with a simpeler design - just two blocks one steel and one aluminium - and that works fine - so there is an issue or a bug somewhere ?  it surely is worth looking into this because apparetnly i m not the only one having this...

[TheCADWhisperer]

@abantu 

I had no trouble changing the body in the file that you attached from steel to aluminum...

[abantu]

well well - that s weird - trying to find out what happens -

looking further i probably found the glitch

and made this screencast :

- in the first part you can clearly see that i cannot change the physical material from steel to alumiunium

- in the second part of the video i discovered that deleting 'aluminium' and add that again - works fine...

this solves my issue but with a deviation - so is there a bug ?  why some people are having this ?

[Phil.E]

In the beginning of the video, you didn't drag aluminum to the body. 

[abantu]

@Phil.Etnx for mentioning that

but it was in the design of course before...

i still think there is a kind of bug - or at least a workflow issue that leads to confusion

e g

if you choose another physical material (other than the default)

and you 'unassign and delete' the old (default) one than what you unassign and delete should really be deleted

which does not seem the case with the 'default physical material'

another thing that i remark

and that has something to do with usability

is that you can drag a material from the list below to the 'physical materials' above - without dragging it onto the object

that has no influence whatsoever in the properties of the object

so why would you allow such a movement ?

or for both cases :

is there a case where you can have two 'physical materials' in the same body ?

if not : why keep all the unused materials used on top ?

i see that rightclicking in the dialogbox above makes it possible to deletes all 'unused materials'

except for the 'unused default material'

[Phil.E]

Hi again.

Thanks for the detailed questions. I think I need to try a different approach than sending you to read the product documentation. So I'll explain it all here to help our conversation more directly.

Default material - as you have noted the default material cannot be unassigned and deleted. But as you'll see by what I explain below, this has zero impact on your design properties.

Dragging materials to "in this design" - think of this action like you would a physical book that you get from a building called a library. The library keeps many many items. You might be interested in more than one. You can "check out" the library items by dragging them into the "in this design" window. What workflows does this allow?

• Customizing materials
• Analyzing materials
• Choosing materials by comparing them

So as you see, there may be many good reasons to "get a few materials from the library to look at" (like books from a library) by placing them into this design.

I don't know about you, but I don't read every book I get from the library. So at some point, you might decide to use just one of the materials, and get rid of the rest, or just leave them laying on your coffee table or bookshelf. If you don't intend to use the materials, they sit like unread books in your room, without any impact on your daily moments.

Two materials, one body - A body can only have one material applied. But a component can have several bodies, each with a unique material. So, you can see that any Fusion design might have several materials "in this design", all being used by various bodies you create.

The Utility Knife sample file shows this pretty clearly:

Okay, so with your questions answered, I'm going to take another attempt to explain how materials are applied to a design.

When you want to change the physical material of a component or body:

• Open Materials, find a material
• Drag it to the object in canvas

Image 1: The part is made from default steel

Image 2: Brass is chosen to be the new material for this part

Image 3: Brass is now the material for this body. (note: The object Properties makes no mention of Steel because the body is not made of steel any longer, nor is it made of both brass and steel combined)

Result:

1. The body is now made from that material
2. The newly applied material appears "in this design"
3. Properties for the body show that it is the new material
4. The "default material" remains in the design, for reasons stated by Fusion (you cannot delete it), but it has no affect on the bodies that have been edited to contain the new material.

Does this help?

[abantu]

tnx again @Phil.E for your extensive answer- much appreciated - it will help others to understand

what you explained is not new to me

but

i have this design where i have chosen aluminium and it stays 'steel' in the properties

unless i throw away aluminium and add that again

besides that it stays not very intuitive

hence the many support questions

1. if i want the default gone than i want the default gone - why keep it ?  there is no reason - under the 'default material' there is this menu which says 'unassign and delete' - but it doesn t delete !  that is confusing because the program doesnt do what it says it will do...

2. ok for the library - but make the applied material 'hero' and the others second level - than there is no mistake possible

this is a great and necessary basic feature

but it s not clear enough

[Phil.E]

Thanks for responding. I think I should also point out I'm only here to explain how Fusion works, today. Your wish to change the program to allow default materials to be deleted is a known customer request, but is not how Fusion works today. I can't change this.

1. if i want the default gone than i want the default gone - why keep it ?  there is no reason - under the 'default material' there is this menu which says 'unassign and delete' - but it doesn t delete !  that is confusing because the program doesnt do what it says it will do...

Actually, the program says it cannot delete the default material. Is that not clear from the messages Fusion gives you? 

Notice how Unassign and Delete is greyed out? That is Fusion telling you that the command is not available for this selection. Sort of like when you are offline, and designs that are on the cloud are greyed out to show they are not currently available.

You have said the quote below already, but the file you provided doesn't have this problem, and the video you provided does not show this workflow. 

i have this design where i have chosen aluminium and it stays 'steel' in the properties

unless i throw away aluminium and add that again

If you don't mind, please post a video showing this design and the following steps:

1. Open Materials

2. Drag Aluminum to the body on the screen

3. Check the properties to see if it says steel or aluminum

4. Post the video and design file so I can replicate the "bug".

Thanks,

[jhaag3]

Your explanation should prove as insight into why this may be a problem for professionals. We are not and never did ask about changing the appearance. We are asking to delete the default material when another material is assigned. Having the default material in the part file can be confusing and problematic when the file is later handled by another designer. Further, I've encountered a drawings that will call the unassigned material (the default) after updating the link. Don't ask me for a file for the solution is exactly as described: give users the ability to remove materials.

I've also read the advice for the "CAD Whisperer" that the user should simply edit the material properties. Companies tend to prefer standardized material names and properties. Editing each property individually is time consuming and requires additional training. This is a great exercise for students, however, it's sloppy practice for professionals.

Seeing as this problem is nearly a decade old, I don't expect a solution. Please stop selling your product. I will forever recommend OpenSCAD before Fusion 360.

[Risa.Oram]

@mike28E6QG

You're definitely not alone in feeling frustrated. I’ve run into similar issues with Fusion when it comes to both physical and appearance materials. It often feels like the program doesn’t function as expected, which makes it hard to trust what you're seeing. I’ve also found it frustrating that you need to set a default physical material in preferences, especially when most designs end up using several different materials, which might not even be the default one you set.

For my projects, the specific physical material doesn’t matter as much since I’m more focused on measurement accuracy. However, appearances are important to me—and yet, they never seem to match the samples in the Fusion library once applied in the design environment. I can’t help but feel like Fusion is still working on getting materials and appearances right, and I hope it eventually works more like Blender in that regard.

It would be great to have the option to skip setting a default material or at least use a truly generic one. Plus, with the bugs (they call it a feature lol) around assigning physical materials, it’s unclear if appearance overrides will look different depending on the physical material applied. Sometimes I just want to quickly mock something up with accurate colors for in-progress screenshots (not have to be bothered with rendering), but I struggle with the lack of white balance, muddy colors, and low contrast. Here's hoping these issues improve soon!

[NeilStansbury]

There is no reason to have a "default material" - the default should be nothing - a "material" with zero weight and zero density. Applying a "default material" to component assemblies is nonsensical and infuriating. The entire material/appearance drag/drop process in Fusion feels like an after thought. Even when you change the default in preferences you can't remove it from a design.

I also have bodies that Fusion won't let me change the material on. It just ignores the dropped material, yet a body in the same component will.

[onetroubledguy]

This problem is infuriating. PhilE's responses above are a huge waste of time. Don't even read them. He's trolling with those stupid "solutions" and "explanations". Why they haven't changed and addressed this issue blows my mind. Fusion is terrible.