Issues with particles editing using OBI Editor

[Pheebau]

Hi,

I am fairly new to OBI and own both Rope & Softbody - Note that i have spent a considerable amount of time to try and understand OBI Softbody.

I know you are working on more tutorials but having video of particle editing for Softbody would be of great help - Yes the tutorial guide is there but it not enough IMO as explaining to customers best practices and show different types of particles editing would be sweet - this is just some feedback so take it or leave it

The issue I am seeing is the following and I have added screenshots to help understand.

I took the deformable barrels sample and tried to edit the barrel footprint by removing 1 particle and trying to add it back - I was unsuccessful in doing so.

1) Removing top particle of barrel blueprint: (I picked an arbitrary one)





All good - the particle was removed.

I then try and add a new one back and I am doing this as I could not add particles to my own blueprint and mesh using the editor so I use the barrel one to test against.

Here is what I see when I try and paint->add some particle (render mode is particle + mesh) - particle is not added or at least it doesn't show.




A closer look:



What am I doing wrong? I have read the guide and watch tutorials I could find and I cannot make this work after trying many things.

Thanks in advance for any help.

[josemendez]

There's a big misunderstanding here. You can't "add" new particles. Particles are automatically generated when you click the "Generate" button, distributed using the parameters you set in the blueprint. Then you can only optimize out certain particles, in case you only want particles in specific areas of the mesh.

The 3 mode buttons (paint, add, smooth) in the property painting brush let you paint properties on your existing particles. In the screenshot, you're adding mass at a rate of 2 kg/second to your existing particles, not creating new particles. See the manual for details:

http://obi.virtualmethodstudio.com/tutor...setup.html

In property painting mode, you can use brush tools to paint particle properties directly on the surface of the softbody. Enabling the mesh render mode is recommended to work when painting.

Most properties offer 3 brush modes:

Paint:
Displaces the current property values towards the one set in the proprerty field. The brush opacity determines the speed at which the values shift towards the target one.

Add:
Adds the value set in the property field to the property values in the mesh. Again, the brush opacity determines the speed at which the values are changed. You can hold shift in the keyboard to subtract instead of add.

Smooth:
Smooths out the property values.

[Pheebau]

Thank you. I have to say I did read the guide more than once but when I saw you could remove particles, I assume you could add some as well

So the white gradient overlay that got created (see screenshots) while editing particles property show the effect (coverage area) on the soft body? Could you please elaborate on this?

What is the goal behind removing particles? I could see the main goal being performance as less particles would lead to some smaller cost in processing? Reason am asking is to better understand when to delete versus editing - I understand both are not mutually exclusive obviously.

I was trying to add particles via the editor because my soft body (convex hull shape) was collapsing too much despite me playing with the Solver and particles properties but now I realize I likely need to play with particle radius + soft cluster radius and regenerate as I am iterating. I also keep seeing the blue links between particles as trusses and I may be misunderstanding what they are in your physics engine but couldn't find in the doc what they are exactly (at runtime)?

[josemendez]

Thank you. I have to say I did read the guide more than once but when I saw you could remove particles, I assume you could add some as well

So the white gradient overlay that got created (see screenshots) while editing particles property show the effect (coverage area) on the soft body? Could you please elaborate on this?

The gradient shows how the currently selected property varies over the softbody surface. For instance, if your selected property is "mass", the gradient represents mass distribution. Excerpt from the manual (visualization options):

The source mesh used to generate the blueprint is rendered. The currently selected particle property is used to drive vertex colors. You can use the range options in the visualization section (see below) to determine how property values are mapped to colors.

What is the goal behind removing particles? I could see the main goal being performance as less particles would lead to some smaller cost in processing? Reason am asking is to better understand when to delete versus editing - I understand both are not mutually exclusive obviously.

The main reason you'd want to remove particles is when you don't want the entire mesh to behave as a softbody. See the elastic character sample scene for instance: only the arms have softbody physics applied:
http://obi.virtualmethodstudio.com/tutor...tbody.html

I was trying to add particles via the editor because my soft body (convex hull shape) was collapsing too much despite me playing with the Solver and particles properties but now I realize I likely need to play with particle radius + soft cluster radius and regenerate as I am iterating. I also keep seeing the blue links between particles as trusses and I may be misunderstanding what they are in your physics engine but couldn't find in the doc what they are exactly (at runtime)?

Adding particles won't prevent collapsing, what you want to do is increase the soft cluster radius. The blue links represent shape matching constraints. These are a type of constraint that tries to keep the overall shape of a particle neighborhood. See:
http://obi.virtualmethodstudio.com/tutor...aints.html