Doesn't work with Skinned Meshes

[josemendez]

I don't even know where to begin. I try working through the documentation and the examples and end up with error after error in Unity 2020.2.1f1. The documentation is so scattershot that I can't even guess where (or if) I'm diverging from the correct procedure for adding a softbody effect to a skinned mesh.

I eventually made it all the way to the end of the example page, hit play, no softbody effects, constant null reference error messages.

Hi there,

Sorry you're experiencing these issues

Can you be a little more specific about what errors you're encountering? I had no problems getting a softbody set up in 2020.2. Let's see if I can help:

The manual is structured in 4 main parts:

• A "introduction" section, common to all Obi assets, that explains basic architecture, simulation principles and core components.
  
• A "constraints" section detailing parameters for each specific constraint type.
  
• 4 sections specific to each asset, in the case of ObiSoftbody, how to set up softbody blueprints, skinning, and character softbodies.
  
• A "scripting" section, again common to all Obi assets, which explains common scripting use cases.
  

It's best to read the introduction first, then go to the section specific to softbodies.

The title of your post is somewhat strange, as softbodies can only work with skinned meshes. The reason for this is that for the purposes of physical simulation, softbodies are represented as a sparse particle cloud. The mesh is then bound to this particle representation using linear blend skinning, which of course requires the use of a SkinnedMeshRenderer (and a ObiSoftbodySkinner component that calculates and updates the skin weights, see:http://obi.virtualmethodstudio.com/tutorials/softbodyskinner.html)

Quote from the manual:

Softbody simulation and rendering are taken care of by two separate components: ObiSoftbody (simulation) and ObiSoftbodySkinner(rendering). The former generates a particle-based representation of a mesh. The latter skins an arbitrary mesh to that particle-based representation, so that they move and deform together.

So by "skinned meshes" I'm going to assume you're referring to the specific case of animated characters. Here's a video tutorial I recorded for another user:



Note that Obi is aimed at intermediate/advanced users, so neither the manual nor the videos explain concepts like linear blend skinning, bone hierarchies, inertial reference frames, etc. It's assumed the user has pre-existing knowledge about these.

Let me know if you're still having trouble with this, if you give me more details about your specific use case I will be able to help further.

kind regards,