Auxetic Foam Cell Structure

Question

I want to create a Auxetic Foam Cell Structure with this technique: Create a sphere in sphere (with boolean diffrence) Generate particles with add particles and replace with mesh sphere in sphere for grid distribution la morphologie est obtenu de cette forme Note: The interference between spheres with holes is equal to the thickness of spheres.

But, if i want the distribution of meshes (sphere in sphere) to be random (50 spheres), how can i do that? Ex:

http://pasteall.org/blend/index.php?id=50818

Can you show a simple example with Boolean Operators? Are you stating one case is easier and one case is more difficult. Is this for a single image or a dynamic image sequence? — atomicbezierslinger, Dec 02 '18 at 17:09
it's a bit difficult with me : http://pasteall.org/blend/index.php?id=50818 — saded, Dec 02 '18 at 18:34
Related (different technique but similar visual result) : https://blender.stackexchange.com/a/81396/29586 — Rich Sedman, Dec 03 '18 at 07:24
The sponge have a thickness with circle or ellipsoid section, with a texture volume is difficult to obtenain this forme same with tissue add-on. — saded, Dec 03 '18 at 12:34
I have moved your Blender File link from the comment to the question. There probably is a better way to do this, which you may have noticed from other people who include Blender File links. — atomicbezierslinger, Dec 03 '18 at 19:26

vklidu · Accepted Answer · 2021-11-02T21:00:11.953

version Shader

Probably would be good to know the purpose of your needs. In some cases could be enough and probably looking better simple Volumetric material with texture type Voronoi or Musgrave.

Under Properties > Render > Geometry > Volume Sampling > Step size decrease value to something like 0.0100. In Blender 2.79 are some changes on Volume Shader, I don't know how to colorised foam to get the same result.

version Mesh

add Cube
use addon “Destructability Editor” or official “Cell Fracture” to crack cube into Voronoi shards

Join all shards Ctrl+J
in edit mode - “Remove Doubles” (W)
select all outer faces and choose delete "Edges"
than delete “Only Faces”

add Modifiers - Smooth (here with Factor 2)

Switch to "Edge" select
Select "Random" from menu like 20-50% and delete selection

Subdivide (W) like 2-4

This created net you can render by adding "Skin" modifier, but its very heavy for calculation, so I used here to add Mball to the scene and add Particle system to the net with "Render" > "Object" > "Mball".

Good vklidu, as for the first solution, the problem is that I can not take the thickness containers. The second solution is a good solution. Can you add a cross-sectional method to obtain sequential images, which are in two colors (voids and texture yellow)?, — saded, Dec 04 '18 at 19:00
Contact me on blenderartists.org . I didn't understand your comment. It isn't the best place for discussion here :) Thanks — vklidu, Dec 05 '18 at 11:02

Robin Betts · Answer 2 · 2018-12-04T14:41:31.293

4

Is an approach like this one equivalent to what you describe?

Using a Rigid Body simulation with collision, pour a bunch of balls into a box:

Choosing a stable frame at the end of the simulation..

CtrlA Apply visual transforms to the balls, and in the Tool Region > Physics, remove them from the simulation.

With the pivot set to 'Individual Origins', scale the balls up to your interference margin, apply the scales, and reintroduce the inside surface of the box, flipped, sealed, and scaled.

Using the Bool Tools shipped add-on..

Make a union of the balls..
and subtract them from the box

The thickness depends on the scaling of the spheres before union..

edited Dec 04 '18 at 14:41

answered Dec 04 '18 at 11:41

Robin Betts

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Good idea, but the problem that this technique does not give shape with desirable thickness. There is a script that can generate random spheres, the technique is to create a sphere in sphere, then we replace the spheres generated with the script by this sphere, here we can adjust the thickness of the sphere, but the problem is how to assemble the interference between these spheres after replacement to get the foam. Note: in the script it is necessary that the spheres is interferent with each other with the desired thickness. – saded Dec 04 '18 at 12:50
@saded (see edit) I'm pretty sure, if your intention in the OP is to subtract the sphere-shells entirely from the cube that encloses them, then this arrangement is the exact equivalent. The physical collision places the sphere-centers at the same relative position as they would have with 1/2 interference/shell thickness, and the scaling makes up the other 1/2? Or do you want the solid to comprise some other constituents? – Robin Betts Dec 04 '18 at 14:38
1

@saded ahhhh! do you want the solid formed by the intersection of the shells? – Robin Betts Dec 04 '18 at 15:02
Yes, It is only the shells that overlap between them, with thickness equal R-r – saded Dec 04 '18 at 15:50

Auxetic Foam Cell Structure

2 Answers2

version Shader

version Mesh

Linked