We will be out of office from December 23th to January 7th. During this time we'll check the forums less often, we'll be back at full throttle soon. Take care, Merry Christmas!
This games uses Obi Fluid for the main puzzle mechanics. In addition to saucing foods, you can cover the customers, walls, and kill zombies with Obi Fluid sauces!
Piece of small feedback - obi SDF adds padding equal to 0.2f during generation, I think it might be wise to make into some parameter or global setting, because for meshes with small scale 0.2 is huge, while for big mesh it's very small constant and it affects result when mesh is open, on edge etc.
is it possible to remove the twist on the rope that is caused by movement upstream? I understand that the rope component doesn't store and calculate twist like rods do. So twist is naturally following the consecutive angles of the particles.
It should be possible in each particle iteration seek to blend the twist toward an upward direction, right? Any advice on where to look?
Hi -- I've read through the manual and tried a number of things, but I'm encountering an issue with particle attachments that I'm hoping to get some insight on.
You can see in the video that the corner of the sail (this is a dynamic particle attachment to a rigidbody at the end of the rope) tends to jitter considerably.
I'd thought that this was a matter of solver settings, but have been unable to make any meaningful improvements -- even cranking iterations up to goofy amounts (20+).
Regarding settings, collision is off, both on a cloth blueprint/particle level, and for the obi rigidbodies involved. The mass of the attached rigidbody and the attaching particles are close (I've tried varying these as well. The only change is that if I increase the mass of the particles to be considerably higher than the attached rb, the issue reverses and the rigidbody starts flickering.)
Worth noting that the issue remains even if the attachment is set to static, and the attached rb is kinematic.
This issue is unchanged on CPU/GPU solving.
This issue is unchanged on RB Interpolation ON/OFF (For both the solver and hierarchy of rigidbodies).
I'm inclined to think that it's due to being a child of a rigidbody, but from my understanding that should be permissable. (Essentially the ship is a rigidbody, which is a parent to all other dynamic elements.)
Simulating Endoscope Tip Articulation with Obi Rod - Seeking Implementation Advice
I'm developing an endoscopy training simulator and need to simulate a flexible endoscope using Obi Rod (due to the torsion support) that interacts with an organ Obi Softbody. I'm looking for guidance on the best approach to implement the endoscope.
Real endoscope Behavior
An endoscope consists of:
- Flexible insertion tube (~160-180cm): Can be pushed, pulled, and rotated along its axis
- Articulated tip section (~10-15cm): The distal end that can bend up to 180° in four directions (up/down/left/right) using control knobs at the handle
- Key characteristic: The tip bending is mechanically isolated from the main shaft via internal pull-wires. When you deflect the tip, it doesn't create relevant opposing forces in the insertion tube body.
What I Need to Achieve
1. Independent Tip Deflection
- The tip section (last 10-15cm) needs to bend smoothly and progressively in response to user input, creating a U shape where the tip points back towards the endoscope shaft
- This bending should NOT propagate forces backward into the main insertion tube. I've done some tests changing particle velocities to shape the tip, and due to the constraints, the rest of the shaft ends up moving while bending its tip.
- The tip can be undergoing a tip deflection while the entire scope is simultaneously being pushed/pulled/rotated, as the endoscope may be moving while the tip is being deflected or held while keeping a specific deflection value. Due to this, freezing the particles to avoid force propagation is not an option, as the endoscope still needs to moove freely.
2. Physical Connection
- Despite the mechanical isolation of the articulation mechanism, the tip is physically part of the same tube
- The tip must follow when the body is moved (pushed, pulled, or navigating through the organ)
- Both sections should interact with the environment (organ walls) naturally, which is a Obi Softbody with surface collisions
3. Roll/Twist Propagation
- When the insertion tube is rotated/twisted at the handle, this rotation should propagate all the way through to the tip, which already happens thanks to rod behaviour.
- This is separate from the tip deflection - the tip can be both deflected AND rotated
Questions for the Community
Main Question
What's the best approach in Obi to implement this articulated structure where the tip can deflect independently without forces propagating to the body? I've done several test and thought of several implementations
**Option A**: Single Obi Rod
- Modify particle velocities/positions for just the tip section
- Somehow prevent forces from propagating to the rest of the rod
- How would I achieve force isolation in this case?
**Option B**: Two Separate Obi Rods
- Body rod + Tip rod connected via ObiStitcher (or other method). Attachments seem too rigid for my needs.
- Apply deflection forces only to the tip rod, and propagate roll from body to tip rod manually?
- Does stitching provide any means for force isolation, or do forces still propagate?
**Option C**: Different approach entirely?
- Is there a better way to handle this in Obi that I'm not considering?
- Custom constraints? Different actor types?
Any advice on architecture, implementation approaches, or Obi best practices for this type of articulated simulation would be greatly appreciated!
I'm getting this strange behaviour affecting the dynamic attachment of a rod to a non-kinematic rigidbody, where the rod is generally quite stiff with 0 or low bend compliance but at the attachment point it sags or deflects away from the attached rigidbody in a very unnatural way, even with constraint orientation on. I tried adding another control point close to the end of the rod as mentioned in the attachments page of the manual, but this doesnt help and gives a very strange shape, given the rest of the rod is stiff. When the attached object is aset to non kinematic this doesnt happen. When I reduce the mass scale of the rod, the issue reduces, but this negitively affects my simulation, I need the rod to have some mass in relation to the end attachments. Do you know what causes this issue and how to fix it?
Kind regards,
Matt
p.s. I have added some images that show the situation, but cant show too much more on a public forum. If you need more context or information I can PM you further images or try to recreate in a new project. Hopefully these show enough.
Hi, I have a transparent fluid in front of a skinned mesh renderer but cannot see through it: it contains blends. How can I fix this? (built in pipeline). Cannot see it when see through fluid but in absence of fluid or from other viewing angles it renders fine.
Thank you.
I want to collide ropes with cloths but can't figure out how.
My setup (one example):
I go in the Obi Cloth "Intercollisions" demo scene.
I add a Obi Rope to the Solver, the settings I leave at default.
I place the rope above the cloths.
I hit play, but the rope falls through the cloths.
I get this error message:
Invalid skinmap in cloth renderer (Obi Tearable Cloth). Make sure the skinmap is not null and suitable for the mesh and cloth blueprint being used.
I cannot use the tearable cloth, this error also occurs in the TearableCloth demo scene.
