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I want to know how to model a porous particle that has a solid or hollow inner space. I want to know how to control the surface thickness in case of the hollow particle.

I found a tutorial, Porous Particle in 3D Graphics –Let’s Shade 3D #006, but it's made by another software.

The second question is: How can I cut a triangle from the particle to illustrate what is inside?

Examples of hollow, solid, porous particle and a cut particle.

Example of porous particle and cutaway view of a particle

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3 Answers 3

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Hey guys ... you provoke me :)
No deformations on surface. No glitches in animation with booleans.


Shape 01

  • add Icosphere
  • Bevel Ctrl+B Vertices V
  • Delete X newly generated faces

enter image description here

Modifiers:

  • Subdivision - Level 2
  • Cast – Sphere, Factor 1 (to get perfect sphere shape)
  • Solidify for thickness
  • Boolean - to cut quarter by another object like a Cube

enter image description here

Notes: Switch to Edge or Face select mode before bevelling so newly generated faces stay selected. For boolean use Exact solver. Smooth shading is used with enabled under Properties Editor > Data Properties > Normals > Auto Smooth.


If you need more dense holes just increase Subdivision to 3 in step one (add Icosphere) in Properties panel (left-bottom in View3D editor).

enter image description here


Shape 02

For version with vertical holes it is a bit more difficult...

  • Add Plane, Subdivide W a few times and as before ...
  • Bevel Ctrl+B Vertices V
  • Delete X newly generated faces

enter image description here

  • Add Sphere
  • Add Shrinkwrap modifier to Plane with Wrap method > Project, Target > Sphere and Apply modifier

enter image description here

  • At a bottom delete corners, select border vertices and search for To Sphere Shift+AltS set 1 to get edge circular. Alternatively you can add one extra Loop cut Ctrl+R
  • Select holes by Loop Select Shift+Alt click on edge in Edge select mode (not Vertex select mode) each hole, Extrude E a bit in Z axis Z, Extrude again in Z much more, Scale in Z to zero and move vertices to Z Loc zero
  • Create a Vertex Group from outer surface (without tubes)

Modifiers

  • Subdivision - Level 2 (to keep holes sharp - exclude edges by Shift+E press 1)
  • Cast - Sphere, Factor 1, Radius 1.02, set Vertex Group of outer vertices (you created before) to let modifier affect sphere without tubes
  • Mirror - only in Z

enter image description here

  • Boolean - use a Cube to cut

enter image description here

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    $\begingroup$ Sweet 😋 - if only booleans worked that well, one can dream... $\endgroup$ Jun 13, 2021 at 16:00
  • $\begingroup$ Booleans would work if your primitive wasnt a approximation fo something in the first place. Its really hard t get a good exact result of something that is not exact. $\endgroup$
    – joojaa
    Jun 14, 2021 at 13:01
  • $\begingroup$ It is a little advanced. I am in the first step, i can not make the plane has vertices inside unless i use grid 7X7 to do look like yours. But the problem shrinkwrap doesn't come well as yours. $\endgroup$ Jun 15, 2021 at 3:16
  • $\begingroup$ Grid is fine too. Shrinkwrap - have you switched wrap method to Project? If issue persist check my blend (Plane_01 is in this state) or share your file. $\endgroup$
    – vklidu
    Jun 15, 2021 at 7:00
  • $\begingroup$ Yes it worked with wrap method project. Then i was able to delete the vertices on the corner. But next, the holes can not be selected to be extruded. how to extrude ? i don't see how to upload my file ! $\endgroup$ Jun 16, 2021 at 7:37
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  1. Create icosphere + cube

  2. add subdivision modifier to icosphere

  3. add boolean modifier to icosphere -> object: cube

enter image description here

  1. select icosphere and enter edit mode with TAB

enter image description here

  1. press CTRL-B to bevel and bevel like this:

enter image description here

  1. change to face select

  2. select one circle face

enter image description here

  1. select->select similar -> polygon sides

enter image description here

then you will get:

enter image description here

  1. Tap X -> Faces

enter image description here

  1. press TAB

  2. Shade smooth

enter image description here

  1. select the cube and change viewport display to bounds

enter image description here

  1. move the cube over the sphere as you need it

Result:

enter image description here

enter image description here

of course you can give it a solidify modifier, as vklidu said, looks even a bit better:

enter image description here

enter image description here

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    $\begingroup$ Nice :). Reminds me of those image-based web tutorials pre-Youtube. After 150 images you feel like you earned the knowledge :). $\endgroup$ Jun 13, 2021 at 8:34
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    $\begingroup$ For better topology use Bevel Vertices Only (Ctrl+B and V). And you can skip selection process if you switch to Edge or Face selection mode that let newly generated faces selected after Bevel. imgur.com/ernOXtT To add thickess use Solidify modifier ... $\endgroup$
    – vklidu
    Jun 13, 2021 at 8:57
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    $\begingroup$ At last! A place for you to use that deleted answer of yours :D $\endgroup$
    – Robin Betts
    Jun 13, 2021 at 10:07
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    $\begingroup$ Mr Chris, I don't know how to thank you. You let me achieve my dream, a difficult dream. Thank you so much so much. $\endgroup$ Jun 13, 2021 at 10:49
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    $\begingroup$ @MajdiAl-Amili : Glad I could help. Please check the checkmark left to my answer, if it is helpful. Thank you! $\endgroup$
    – Chris
    Jun 13, 2021 at 10:51
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Let's try with, hated for good reasons, boolean workflow, mainly because I think the tutorial you linked uses booleans. Though there the holes aren't distributed evenly:

The above could be achieved by making a cone, and adding two array modifiers, but we can do better, like Chris, so let's try but with boolean modifier.

The advantage of boolean is that you don't have to go through a puzzle on proper topology, so this solution should be more versatile (e.g. when you want to replace the cones with cylinders as on one of your reference images). The disadvantages are, however, plenty:

  • the resulting topology may be very heavy (a lot of triangles)
  • booleans are often buggy and cause issues with animations due to inconsistency
  • there are also problems with smooth shading and resolving them can be quite tricky (normal data transfer from the original uncut sphere)

Add an Ico Sphere (because that generates equally spaced triangles), then add a cone, edit it, using Increment Snapping (hold Ctrl or click the magnet button) move the cone so that the tip is at the world (sphere) center. I also move the base up because I find it more natural to look an an object from the top, but that's just my preference. Then I rotate the cone to make it roughly fit a triangle (keep in mind in this situation you have to rotate along green Y axis, not red X axis, due to how the triangles are distributed). If you readjust the distance of the base of the cone to the center, remember to use G, Z but in local coordinate space, ignoring the rotation of the object.

Let's name this cone Cone.A, and duplicate it, and name the duplicate Cone.B, let's also Hide Cone.B for now. Likewise rename the Ico Sphere to Ico.A, and create a duplicate Ico.B, hide the latter.

Select Cone.A, then Ico.A, Ctrl+P, O.

Edit the Ico.A, select the triangle overlapped by the cone, Shift+S, U:

Now in object mode, with the Cone.A selected, press F3 and search for Set origin to 3D cursor. In Numbers panel, clear (set to 0) cone's rotation as well as location, so it's inside the sphere, then with Ico.A selected, change its instancing to Faces:

And we got the cones:

Though there's still some room for additional cones - exactly where the Ico Sphere's vertices are... So let's hide the Ico.A and Cone.A, unhide the Ico.B, Edit the mesh, select everything, Ctrl+B for bevel, scroll down (mouse wheel) for minimum number of edges, C to clamp, and move your mouse to maximize the bevel like so:

M, B, increase the range until you remove all small faces:

Adjust Cone.B to the top face of Ico.B just was done with A variant. Don't resize the cone, though. Result:

I'd advise hiding both sphere, going into edit mode of each cone, hiding everything except the base face, then in object mode unhiding everything, selecting both cones, going to edit mode, and then scaling the bases so they have satisfying size:

Select Cone.A, Ctrl+A, M (Make instances real), Shift-click one of the cones to activate it, Ctrl+J to join those cones into a single mesh/object. H to hide it. Repeat for Cone.B. Remove the rest. Unhide the cones, select both, Ctrl+J to join them. Now you have the equivalent of the first screenshot in this post.

You can now create a "proper" sphere to your liking, e.g. UV sphere. You can add another sphere to cut the insides of the main sphere, you can add a cube to cut a fragment of the resulting shape... Once you're done, Hide the cones, as well as other objects you use for cutting (or change their display to bounds, as I did for the inner sphere and the cube) and add boolean modifiers like so (before doing so better save your project :D):

And here's an underperforming animation, notice the bugs...

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  • $\begingroup$ This can really enrich the the imagination and understanding, thanks a lot. $\endgroup$ Jun 13, 2021 at 12:09
  • $\begingroup$ Hi Markus, although you got an upvote from me for you answer - it looks like that some beginners have difficulties to reproduce it and so someone asks for a video about it...maybe you want to help... $\endgroup$
    – Chris
    Jul 13, 2021 at 6:28
  • $\begingroup$ @Chris I see, Edu39 had some problems. I'll think of a way how to clear the answer, though ideally he would write here and we could create a chat for him. $\endgroup$ Jul 13, 2021 at 9:30
  • $\begingroup$ thank you! I have no idea how to create that chat... :D $\endgroup$
    – Chris
    Jul 13, 2021 at 9:33
  • $\begingroup$ @Chris I know how - just spam here until the option appears ;) but let's wait and see if Edu39 even comes here. $\endgroup$ Jul 13, 2021 at 10:52

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