Cineversity

My question: Is the alembic file real geometry, or some proxy file structure that references the geometry without actually reproducing it?

The backstory: I have a planetary gear model with some complex Xpresso animation that I am trying to export to GLTF for viewing through a browser. After many attempts, I settled on a 2-step process that involves exporting it as an Alembic file to clear out all the Xpresso and from there, exporting to GLTF. That almost works - some of the animation comes over, and some is lost.

I’m still analyzing (it’s a complex model) but that got me to wondering if the alembic file is at the root of the issue? I learned that I could convert the alembic proxy to editable mesh, which made me think that to capture missing animation I needed to convert all the pieces to editable mesh. If so, is there a global command for this, or do I have to step through piece by piece?

I can send it to you by private link if you’d like to evaluate.

Thanks

Hi mford610,

The Alembic file contains all data needed to know, to reproduce the file. A good test is, of course, to merge it into a scene and see what works.
If at that stage a problem shows up, then glTF will not get the information, to state the obvious (sorry about that.)

The manual about limitations:
The exported animation length orients itself to the Minimum Time and the Maximum Time setting in the Project Settings menu.

Please check this out if you haven’t already.
https://help.maxon.net/us/index.html#FGLTFEXPORTER-GLTFEXPORTER_GROUP

Without any scene file, it is hard to tell. What animation is not coming through, and how was that animation created? Can you bake it, switch Xpresso off, or even delete it (use a copy of the scene to test this!)
Is it moving anyway? If so is the round trip with Alembic working?

As usual, guessing is wasting time on your side. A scene file is the only base to clear things more solidly.

I have tested the last build, and I can’t produce any trouble.

All the best

Thanks for the file, mford610.

It is always the best way to support projects to see what really happens. Guessing feels like amateur hour to me, while wasting your time.

I got an error for the missing IGES-importer when opening the original c4d file.

I would need way more time, but I think that is exactly the problem with this file. It is huge and has so many parts in it that have no need to be there or to be separated into many child objects, only to require the need to be animated individually in the abc file.
For example, the “Quick Disconnect Bushing” shows up in the alembic file with 399 objects, and it could be just one without taking anything away from the model. I really had to search where it is. Deleting it would be my suggestion.

Most cogwheels (planets) are based on three elements, each could be just one. Whereby the Xpresso has the source sometimes below the target, which is not advised. X manager> X-Group. This is just housekeeping to have that running from top to bottom as the information flows. It will not always harm your animation, but more often than not, it does. In the thousands of files, I have gotten in the past 16+ years, I have not seen it often organized. So, it is quite common.
My suggestions, things that rotate around the same axis, with the same speed, etc. should be merged into one object. I assume that will clear the whole animation, and leave you with just a few dozens of objects.

Any screws/bolts that are in the scene should have no thread, nor should the object that holds the screw. Why? Because it takes a huge amount of processing to keep that geometry, and it is literally not seen at all.

In the Alembic file, I saw a lot of Time Offset values. Which would be an easy fix, if the whole scene would not consist (in the abc file) of 1738 objects! Since selecting them all, doesn’t give me that parameter at once, I will not go there. I did so with a single object, and all went fine.
Explore the settings of your Cinema 4D file, and when you explore the Alembic file, set it to the complete duration of your animation, then go through it, you will find the animation somewhere.

I know you have it up and running in Cinema4D. But to deliver it to a wide audience, it should be as simple and small as possible. It took even on a new iPad Pro quite a while to get loaded. Which I think is not ideal.

So, I hope my suggestions are not seen as a critic and more as support. It will be a great example of a glTF animated file, I’m sure.

My best wishes for your project.

P.S.: One question the belt running the Zoetrope and the magnets under it work together, so the magnets can “pause” the Zoetrope until the belt pulls strong enough to move forward again. I can’t find that motion in the f-curve, what do I miss?