2
$\begingroup$

I am a student looking at microstructures. Therefore I am using the Particle System to create a lot of droplets.
To mimic a microscopic image I want to make a slice of the system.
I can do this by using the shortcut Alt+B. (see image) enter image description here
But by using this shortcut, rendering isn't possible.
Does anyone know how to make a slice of a Particle System? The Boolean Modifier, Knife tool or Bisect don't work for the Particle System...

Thanks! Jantine

By using nodes, I get black artefacts: enter image description here enter image description here Suggestions for a solution? I guess these black shapes are remaining of part of the balls that overlay each other, which is also something to solve...

Thanks!

Is it possible to fill these spheres? So that the inside is solid green? enter image description here

Thanks!

|improve this question
$\endgroup$
  • 1
    $\begingroup$ Try increasing amount of transparent bounces in the Properties editor > Render tab > Light Paths rollout > Transparency until black spheres disappear $\endgroup$ – Mr Zak May 2 '18 at 13:03
  • $\begingroup$ Hello. It is advisable not to keep a thread going by adding follow-up questions to your original one. Your follow-up would've been better added as a comment to my answer. Anyway, what you now request is possible although a bit more computationally expensive in my suggested node setup. It requires using the volume shaders. I don't have time to work on an example right now, I'll probably do it tomorrow and add to my answer. $\endgroup$ – Nicola Sap May 3 '18 at 9:13
  • $\begingroup$ If this is your intended result (full slices, not hollow) and you don't need to animate the particles, a different route can be followed that involves "making the duplicates real" and Boolean modifiers. I'll probably post a second answer with this route. $\endgroup$ – Nicola Sap May 3 '18 at 9:17
  • $\begingroup$ I would appreciate that! $\endgroup$ – Jantine May 9 '18 at 10:55
3
$\begingroup$

You can slice them at render time (i.e. the full geometry will still be there, but only the relevant slices will be rendered) by using Material nodes:

Say you want to render only the portion 0.5 < Z < 0.9. Then, as your sphere's material, use a Mix shader:

enter image description here

The Mix Shader should be used to mix your material (whatever that is, e.g. a green Diffuse) and a fully white "Transparent BDSF".

The mixing "Factor" is either 0 or 1, controlled by a set of "Math" nodes that check whether the "Z" coordinate is in the desired range.

Result:

enter image description here

Note (after your edit): if there are many particles, the "Transmission" value under "Bounces" in the "Light Path" Render settings should be at least twice the number of particles that can be found along a lightpath from your point of view. ← If this doesn't make much sense to you, just increase that value until it looks right.

|improve this answer
$\endgroup$
  • 2
    $\begingroup$ Another (less flexible) method would be to use camera near/far clipping. $\endgroup$ – B.Y.O.B. Mar 28 '18 at 14:45
  • $\begingroup$ Thanks for your answer! But I still have some problems with this. To which object are all the nodes in the node editor added/linked? $\endgroup$ – Jantine Apr 6 '18 at 7:35
  • $\begingroup$ The one showed is the Material Node structure for the "sphere" object. (I assume that you have a single sphere that gets duplicated by the "rendering > object" option of the particle system. That sphere must get this material) $\endgroup$ – Nicola Sap Apr 6 '18 at 8:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.