BB: best way to create a new type, from copying another

theoryshaw

Does anyone have a good workflow for creating a new type, from another?
Intuitively, I'm doing the following, but she's a no-go.
vid: https://www.dropbox.com/s/apcmh2emcn3dwsv/2021-09-23_11-43-51.mp4?dl=0

Coen

Slightly related, what's the Blender equivalent of type and instance parameters in Revit?

I am using Alt + D, to copy an object so all the objects keep modifiable (if that's a word).

How would this work with IFC in BlenderBIM? My knowledge of Blender is still very limited, I have the tendency to compare everything from what I know, in this case Revit.

Are there any suggestions how to keep information in the BIM/IFC parametrized in an instance/type manner using BlenderBIM?

Moult

Thanks for this question. First, fixed bug when copying types and fix and also fix and also also fix and also also also fix.

OK - so basically now it should just mostly work now out of the box, but here's the details.

In Blender, there are many ways to copy objects. You can Copy/paste (i.e. Ctrl-C/V), you can duplicate (Shift-D), or linked duplicate (Alt-D). Indirectly, you can also separate (P). There are probably more that I can't think of right now. Out of those 4, the first 2 are kinda identical, and the 3rd (linked duplicate) links the mesh instance together so when you edit the geometry of one, the other is also changed. The fourth breaks one mesh into two objects.

Now when you copy an object in Blender, we intuitively want that object to be copied in IFC as well. To solve this, we write some deep magick code that overrides Blender's built in duplication functions so that it also copies the IFC element. In addition, in IFC we have our own rules of when the mesh object should be shared. So whereas in vanilla Blender you can use Alt-D to link duplicates wherever you want, in the world of BIM, that's a no-go. In IFC (and in almost all BIM) if your object has a construction type which has geometry, your object must use that geometry. So if you've got a chair FurnitureType with a chair mesh, all instances of that Furniture that is a chair type, must use the chair mesh.

So our deep magick override code forces both the Shift-D and Alt-D function to basically be identical, and the BlenderBIM Add-on decides for you whether the meshes are linked based on your IFC construction type.

Now the deep magick doesn't go deep enough apparently to override copy paste, which is slightly different in the Blender world to Shift-D/Alt-D. I suspect the difference is that Blender's copy paste (which you accessed via that right click option) works not just on objects, but on all sorts of fun things in the Blender interface like keyframes. The implication of this is that the best I can do is override the Ctrl-C, Ctrl-V hotkeys. So as long as you use Ctrl-C/V it will auto copy the IFC element. If however you right click and use the context menu (come on!) like you did in the video I don't currently have a solution and you'll have to fallback to a manual copy.

The fallback, a manual copy, can be found by pressing the "Copy Class" button in the IFC Class panel in the object properties tab.

Sorry for the long explanation, but hopefully in the majority of cases now it will Just Work (TM).

theoryshaw

Apparently the following way, is not the way to create a new type from another. :)
What sauce am i missing?
https://www.dropbox.com/s/mwks459ju2i9sww/2022-02-18_09-33-51.mp4?dl=0

theoryshaw

for those passerbys...
https://www.dropbox.com/s/x2hee3fogpizqkg/2022-03-03_15-34-04_Blender_blender.mp4?dl=0
It seems the best way is to just copy the type in the 3D viewport, not in the outliner.

Gorgious

That was a... refreshing choice of music for a Blender video but I enjoyed it ><

One of the many gotchas of Blender, the outliner operations are not the same as the 3D viewport operations...
Had a problem with library overrides once and the developers acknowledged this is confusing but not a bug ^^
There is also Delete and Delete Globally which are not the same thing and the outliner's "Delete" has the same behaviour as the 3d viewport's "Delete Globally" if that was not confusing enough :)