Cineversity

Hi There

I’m trying to rig an Octopus using the Joint Falloff field system, as per this tutorial @18:44 http://www.youtube.com/watch?v=RUeY1HMXvFM​. (The auto rigging / bind system make a mess of the middle body area).

However, I’m having issues with the binding - see screen caps attached. Some of the geometry is getting left behind.

I’ve tried enlarging the field spheres (even to a lot larger than the tentacle’s diameter), but that only ​helps a bit and eventually the geometry falls outside the influence of the field sphere.

Therefore I don’t think its an issue with size/shape of the sphere… and also because if I “bake falloffs” down in the Weight Manager, it then works fine…. maybe because the baking normalises the values? But baking it down, kind of defies the point of using falloffs, since they can be adjust/tweaked on the fly. It feels like maybe the sphere’s aren’t exerting 100% weights?

If anyone has any ideas it would be hugely appreciated???

Many thanks,
Adam

Hi Adam,

I don’t think that baking them out is defying the idea. If you leave them active, every single point will be calculated for every single frame, with Sub-Frame Motion-Blur even more so. (Freeze instead would be an option, but the complexity grows.)

Images do not really communicate most of the time, especially not with this amount of joints. The Spheres seem to sit on the Joint, which means they work as well backward; that is not really how things work. Perhaps I can’t see it on the little shots. I would think that a Capsule would work much better and moved a little bit more into the position a “bone” would cover the space.

I have set up three little examples, perhaps this illustrates the problems.
https://www.amazon.com/clouddrive/share/jxJMyfGAazymRyXn46qMkkY8uske6uOYAo2j1r0bZOU

I do not comment on 3rd party tutorials. However, the Tutorial-Forum is for Cineversity Tutorials only, and the idea is to use only the Help with this tutorial button to open a new question. This is designed to keep things organized. Thanks.

All the best

Hi There

Thank you so much for this - that all makes sense… I will give it a try tomorrow!

Best wishes,
Adam

Thank you, Adam, for the reply.

Let me know if there is anything I have missed, or perhaps there is more to discuss about. I’m happy to look into it.

For anyone following along:
https://help.maxon.net/us/index.html#OCAJOINT-FALLOFF_GROUPFALLOFF

I can provide an upload link if you like to have your model private, place the word “Private” in the name of the file or folder. I will keep the file itself out of the public but perhaps showcase with images/screen capture (please let me know if that is OK).

(I use for security reasons only DropBox, Amazon, Adobe, Apple, or Google cloud services. Again, I’m happy to provide an upload link.)

Cheers

Thank you. I may try and use “auto weight” in the weights manager for most of tentacle and just use a few fields for the joints that go into the body (which was the area that was causing the automatic bind problems)... if that makes sense?

Adam,

You might try different options of the way Auto-Weight is calculated, Distance, Heatmap, Volume.

I’m not convinced that setting up all the Fields is less work than selecting problem areas and setting the weight as wanted. It feels just like a lot of more complexity to an already massive amount of Joints.

My typical way of answering is based on scene files. I’m not guessing what could work, nor answering from memory. Over the past 16 years of replying in Fora, has shown that this is the only way to not waste time on both sides. This is, BTW, a reason why I really don’t give a lot of weight to images; answers based on such is often memory-based (i.e., by default old, not updated, not case-specific, in other words: questionable.) Scene files work, or they don’t, it is as simple as that.

However, I can’t really stress enough to take advantage of this presentation:
https://www.cineversity.com/vidplaytut/siggraph_2015_rewind_bret_bays_weighting_workflows_for_cinema_4d_character

Perhaps not your target, but it came to my mind as well: (speaking of complexity…)
https://www.cineversity.com/vidplaytut/siggraph_2016_rewind_-_chris_schmidt_creating_advanced_controllable_dynamic

Cheers

Understood… I’ll have a try again tomorrow and hopefully find a solution using your suggestions, but if I’m still having trouble then I’ll definitely upload a scene file. Thanks again for all your help!

Adam,

The forum’s file limit is set to 4MB, and it must be a zip file. However, the MIME-type is often not correctly recognized, and then it fails. Sorry about the trouble.
I have sent you an upload link.

My best wishes.

Some points to consider, while using only a Falloff based weighting.

Are they child objects of joints or stay stationary? Each situation creates a couple of problems.
Stationary, if the axis of the “character” receives any change, all weightings might be off. If the character is not moving, things stay stable.

If the falloffs are moved with the joints, the total value of each point must be 100%, which is hard to keep, given the rough details that falloffs have compared to the point-based mesh. overlapping values will be handled with an evaluation. This means the mix for each point might undoubtedly change. If the total of all values is below 100%, then points are moving not all the way, which is only in small distances, if at all, tolerable.

Falloffs centered on the joint, will affect the parent joint influence of the points. This will result in a skin that seems to be moved by a broken bone. Which is highly unlikely in regular use.

The information on single-point values is not given. This means no information about how much each falloff/joint contributes is not available.

Any IK set up with Stretch, and Squash options will have no option to change the falloff accordingly. This will lead to a highly unpredictable deformations. Of course, an Xpresso set up might help here, but is the complexity worth it?

The idea of using the Freeze option in the Falloff might come to the rescue of some problems mentioned so far. The question of why not bake the values directly, instead of such a huge management requirement needs to be addressed.

A falloff might touch other areas of the surface that will be affected unintentionally.

The values produced, can’t be stored in a file (Weight manager> File: Save/Load.) This creates a limiting situation, as the set up must stay intact. If that is needed, it might be of minor importance.

There are, without a doubt, even considering the problems, perfect uses for such weighting, that it should not be avoided at all costs. The option to dynamically change the weighting, or have interactively auto-weight overlapping areas, can lead to new and otherwise impossible solutions.

I do not assume that this list is complete, nor a fit to any possible set up, but the use of falloffs should be done with good knowledge about its pros and cons.

Thanks for the file, Adam.

I want to suggest one point. The mesh is very dense, based on the details needed. This results in the visibility of the joint-structure. This means that the tentacles are not as smooth as they might be in nature. This can be changed with smoothing.

If you have all the joints in the WeightManager, you can load this list into it (do it with a copy of your character). This is a pure value list and gives nothing from your work away.
https://www.amazon.com/clouddrive/share/HbAv0Wm2SrSUYhGdW91UOoQsYqizKRzDJmnrTXZDRi6
I will soon disable this link, as it has no value for anyone else.
In short, I selected Joint.3 to Joint.9 each time and used a 3.5cm for the initial smoothing.

Here is an example of a smoothing process that I have applied first to all the main joints, then to only the larger ones, then only to the largest joint. In this way, a smooth result is achieved.
Project file
https://www.amazon.com/clouddrive/share/hcP0WI6kxNMwkkLUn2nBaXtGkJW7hQniiI1Q36qPG8N
Screen-shot
https://www.amazon.com/clouddrive/share/3XjDw7U17Mg5PLI1nvbt15SJv6afcCVTrnd6M5LT76f

I hope that supports your work.

Have a great weekend

Hi There - thank you so much for this. That all makes perfect sense!

Much appreciated.

Have a great weekend.

You are very welcome, Adam, thanks for the kind reply.

My best wishes for your project with this impressive character.

Cheers