14-07-2023, 06:37 AM
(This post was last modified: 14-07-2023, 06:40 AM by josemendez.)
(14-07-2023, 06:21 AM)danazoid Wrote: Hi, I am trying to use a tool to push on cloth in VR.
I have 2 issues.
1. Cloth push-back on tool
Is there a way to increase the force exerted by the cloth on the tool?
As I understand it, PBD starts from position, then calculates velocity, which is then used to calculate impulse.
So I increased the mass of both particle and tool and it helps quite a bit. Are there other ways?
The only way to increase acceleration (that is, the effect a given force has on an object) is decreasing mass. Decreasing the mass of the tool compared to the mass of the cloth will make the cloth move the tool around more easily. Doing the opposite (decreasing cloth mass and increasing tool mass) will make it easier for the tool to move the cloth.
(14-07-2023, 06:21 AM)danazoid Wrote: 2. Object passes through cloth
The cloth resists bulky shapes like sphere colliders nicely.
a) but I have issues with long and thin objects like a cylinder (capsule collider). The ends of the cylinder tend to be resisted fairly, but the sides of the cylinder slip through, even though barely any force is applied.
I suspected maybe there weren't enough particles, but increasing particle density (via mesh) and particle radius (via cloth blueprint) does not help.
b) I enabled surface collisions which works with bulky colliders but not the cylinder sides.
I observe that the object passes through the cloth upon a certain force (and not particle separation). Is this observation correct?
Is this object a rigidbody? If so, it shouldn't pass trough the cloth as long as their mass ratio is sane (typical rule of thumb in most engines is 1:10, that is, don't have objects that are more than 10 times heavier or lighter than the other interact with each other).
This is a limitation of all physics engines, large mass ratios (and hence, large forces) require finer temporal resolution (that is, a smaller fixed timestep) to be solved accurately.
(14-07-2023, 06:21 AM)danazoid Wrote: Side question: what does the setting "one-sided collisions" on the obi cloth component mean? I could not find it in the manual or the forum.
Makes cloth collide against other cloth objects only against the front-facing side of the geometry (that is, the side that vertex normals point towards). This is useful to avoid tangling when using multiple layers of cloth.