COMPOUND SHAPES - Blender Quickie
Why Blender Stack Exchange recommends it
Blender Stack Exchange users link it when explaining how to use Compound Parent rigid body shapes to get accurate collisions or to drive complex mechanisms with simple proxy colliders.
Recommended by 1 people across 1 different months, 2020 to 2022.
What it is
A three-minute Blender Quickie from CGMatter showing the Compound Parent collision shape added to rigid body physics in Blender 2.9. It explains how a simple low-poly parent can act as the collider for a detailed child object.
What people said
Recommends Jack Peach · 2022-03 · Blender Stack Exchange · on “Multi Rigid Body hinge joints not keeping alignment”
I have solved the issue by using a very simple Rigid Body "skeleton" structure and parenting it to the actual part. I followed a path similar to: [this video] and download.blender.org/demo/compound_collision_chain.blend For example, use a simple wire mesh Rigid Body to represent the real mechanism (the leg link and the hinge joints). Then parent that part to the real geometry (the actual high poly count leg part). And example is below: The selected box is the "high poly count" leg link. It is a Rigid Body and its Collision Shape is "Compound Parent". [LINK] The simple wire mesh Rigid Body part shown below is the actual Rigid Body part that is used for the physics calculations and is much easier o
Recommends Jack Peach · 2022-03 · Blender Stack Exchange · on “Multi Rigid Body hinge joints not keeping alignment”
Hi @Chris, I have solved the issue by using a very simple Rigid Body "skeleton" structure and parenting it to the actual part. I followed a path similar to: [this video] and [LINK]
Cites moonboots · 2020-08 · Blender Stack Exchange · on “Rigid Body objects pass through Basket”
In 2.9 there will be the Compound Parent shape, explained here [this video] by CGMatter, that may make things even more accurate, for the moment here is a solution with Convex Hull that works: First, don't keep your vertical cylinder. Also, join the trim of the basket to the basket, for the moment it is another object without any physics. If you join it to the basket it will be taken into account In the Properties panel > Scene > Rigid Body World , increase a bit the Steps Per Second value up to 100, I don't know how it works exactly but it looks like it helps to simulate physics more accurately. Select one of your lemon, in the Properties panel > Physics > Collisions > Shape , choose Convex Hull
Cites Prime007 · 2020-10 · Blender Stack Exchange · on “How do to use just edges as Compound Parent?”
2.91 introduced a new collider shape called 'Compound Parent'. If I'm not mistaken the main idea is to have a low poly parent which acts as collider instead of the high poly child while calculating rigid body physics.(as seen in this video [this video] ) but the chain example seen on [LINK] uses just edges as collider.I would like to know how it was done. and i would also like to know if there is difference between using a 'copy transforms' or 'child of' constraint instead of compound parent. I tried having multiple edges as child objects with mesh collider but the mesh just passes through each other instead of colliding. [LINK]