Oh, while you're here, I recently started exploring the possibility of starting a small shop. When I looked into Shopify I had absolutely no idea how to get started or how much it cost and your website failed to even come close to answering those things in the few minutes I had to investigate. Whereas with SquareSpace provided those answers in seconds.
Show HN: A tool for motion-capturing 3D characters using a VR headset
21–30 of 32 posts
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#22Oh, while you're here, I recently started exploring the possibility of starting a small shop. When I looked into Shopify I had absolutely no idea how to get started or how much it cost and your website failed to even come close to answering those things in the few minutes I had to investigate. Whereas with SquareSpace provided those answers in seconds.
Just went back, have no idea how I could have gotten so confused. Had ended up on a list of add-ons and such.
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#23Earlier quoted context omitted.
Wow that's super cool! That's definitely the biggest challenge - how to keep the size of the mocap data small. Our library is not the best at that, since it simply records everything to Alembic files, which are quite heavy. Best of luck with Explayn. I really like the idea of learning from mocapped lessons.
Thanks for the kind words! Yes, file size for live action or shipping directly in an app is always an issue. I may actually contribute some code, my file format is no rocket science, just a bare set of floats with some metas, not even some diff encoding between frames, so quite easy to interpret between languages and platforms.
Take a look at the MCAP file format (https://mcap.dev), we invented it for the robotics industry but it’s a generic write-optimized container format for time series data. Since it’s a container format, you need to choose a serialization format as well such as flatbuffers or protobufs.
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#24This is extremely cool!
I haven't much of a clue on motion capture. But, the capture I want to do requires feet, hands, face, shoulders, arms, knees, fingers, AND the ability to do it in any position. Curl up in ball. Roll over on the floor. I want to capture more than just a head and hands upright but AFAIK there's no solution under $20k.
See user name. if I want to make pr0n, I need to be able to capture those positions. Is there anything that can do it on the cheap?
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#25Earlier quoted context omitted.
Wow that's super cool! That's definitely the biggest challenge - how to keep the size of the mocap data small. Our library is not the best at that, since it simply records everything to Alembic files, which are quite heavy. Best of luck with Explayn. I really like the idea of learning from mocapped lessons.
Thanks for the kind words! Yes, file size for live action or shipping directly in an app is always an issue. I may actually contribute some code, my file format is no rocket science, just a bare set of floats with some metas, not even some diff encoding between frames, so quite easy to interpret between languages and platforms.
For a body, with bones, since they can't stretch. All you need is rotation at each joint. You can get away with 10/11 bits per axis.
So for a full body you should be able to compress to 200 bytes per frame for 50 joints. That would mean 300k for 1 minute of animation at 30fps. Interpolate to get 60fps. That doesn't include faces.
If you do faces like Apple does, which IIUC is just N morph targets where N is like 15? Those are 1 weight each and you could easily make those 1 byte per weight or less so that's 27k for 1 minute of animation
Both of those could probably easily be compressed by storing deltas like draco or fit to curves for lots more compression.
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#26This is extremely cool! I haven't much of a clue on motion capture. But, the capture I want to do requires feet, hands, face, shoulders, arms, knees, fingers, AND the ability to do it in any position. Curl up in ball. Roll over on the floor. I want to capture more than just a head and hands upright but AFAIK there's no solution under $20k. See user name. if I want to make pr0n, I need to be able to capture those posi…
Curling up in a ball and rolling around on the floor seems like a worst case for a lot of motion tracking setups. Systems based on wearable sensors won't work because you can't comfortably roll around in them, and single-viewpoint systems like the Kinect get confused when they can't see your whole body.
Have you tried getting a bunch of Kinects and doing some kind of sensor fusion? I don't know what the current state of the software is but you can buy the hardware for <$100 each used.
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#27That's great!
I assume the hand capture (+ head position) doesn't give you enough to apply inverse kinematics reliably (i.e. better than VRchat), is that correct? It's a naive assumption on my part given that wrists aren't captured, but perhaps there are really smart ways to solve this. It feels like it could be a "next step" to have upper-body motion capture.
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#28Earlier quoted context omitted.
Thanks for the kind words! Yes, file size for live action or shipping directly in an app is always an issue. I may actually contribute some code, my file format is no rocket science, just a bare set of floats with some metas, not even some diff encoding between frames, so quite easy to interpret between languages and platforms.
For a body, with bones, since they can't stretch. All you need is rotation at each joint. You can get away with 10/11 bits per axis. So for a full body you should be able to compress to 200 bytes per frame for 50 joints. That would mean 300k for 1 minute of animation at 30fps. Interpolate to get 60fps. That doesn't include faces. If you do faces like Apple does, which IIUC is just N morph targets where N is like 15?…
Thanks! Yes, that’s the way to go. There is only a compromise between code simplicity/specialization and compression performance. And another point is the ability to use the format in memory without too much decoding or overhead when opening the file, random access for fast forward etc (when doing delta encoding) etc. (And I actually need strech too because my NPC interacts with objects, so the arm/hand bones should be at their exact place at replay, that’s 32 bones just for fingers.)
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#29Earlier quoted context omitted.
Thanks for the kind words! Yes, file size for live action or shipping directly in an app is always an issue. I may actually contribute some code, my file format is no rocket science, just a bare set of floats with some metas, not even some diff encoding between frames, so quite easy to interpret between languages and platforms.
Take a look at the MCAP file format ( https://mcap.dev ), we invented it for the robotics industry but it’s a generic write-optimized container format for time series data. Since it’s a container format, you need to choose a serialization format as well such as flatbuffers or protobufs.
Thanks for the pointer, I will definitely have a look at this format, I was not aware of this.
Re: Show HN: A tool for motion-capturing 3D characters using a VR headset
#30That’s cool! What would the typical use case for this be (and why did Shopify build it)?
We actually built this to easily add hands to this concept video: https://twitter.com/StrangeNative/status/1613218237969494017... Animating hands by hand (no pun intended) is horrendously difficult, so our 3D artist asked if we could help. We built this within Shopify's Spatial Commerce team, which is a team that explores the intersection between AR/VR and commerce. Here are some of our other projects: https://twitte…
I am constantly impressed by what your team shares and the practical application of XR concepts. I find myself pointing people to your demos frequently and hope to see one or two implemented through to a purchase experience I can try at home. Thanks so much for all the output !!