How to replace the multiple parts of a mesh with other parts?

Imagine the candy sprinkles on a donut. I want them to have a different shape. I know I could use the Obj Data to change one mesh for another.

But probably that approach would not work for this …
Any ideas?

Thanks guys :slight_smile:


Hi, I’m not entirely sure as I have not used this functionality, but i would recommend looking into Dupligroups… this basically works by grouping the objects together and then randomly selecting objects from the group.

Thanks Lgowans, I’ll look into that right away!


Well you could you the particle system to achieve the donuts sprinkles. Make however many different types of sprinkles you want and then Group them(cntrl-G). Now take your donut into edit mode , select all the vertices and assign them to a new vertex group. Set the the vertex group weight to Zero. Now open the particle system tab and create one. Change from emitter to hair. Under emissions you can set the number to what ever you need. Down the particles system tab you will see 4 tabs select group. Under that is a dupli group menu… choose your group. Now go down to vertex groups and on the density menu add your group. So now your object should not have anything on it because we set the weight to zero in the vertex group. Now you can swap to weight paint mode and paint where you want the object to go. Under the particle sytstem you can set the objects to random selection and size.

Excellent! Thank you so much Cybermonk! This is what I needed.
I was able to follow until I arrived to the Density menu… there you lost me. Could you elaborate on that part please?


The density menu will be on the particle tab down toward the bottom. It’s under vertex groups. Just click on that and it should open up. At the density menu you select your vertex group(on the donut). It uses the weight of that vertex group to distribute the group objects. Since you set that vertex group to zero weight it should not show any of your group objects. Now you can go into weight paint mode and paint where ever you want the sprinkles to go. I hope this helps :slight_smile:

Thank you so much for the explanation Cybermonk :slight_smile:
I’ll give it a try asap!


No problem good luck with your project.

Ok after going over every single step in the following tutorial (which I adapted here from 2.49 to 2.75a) still is not working for me :frowning:

This is how it looks for me so far, but when I get out of Weight Paint nothing happens. Where are my sprinkles?

If you don’t mind reviewing these steps in case I’m missing anything…

For simplicity sake I removed any unimportant info. Anything that WON’T get in the way of getting this done fits this bill.

Adapted to Blender 2.75a from = February 18, 2009 | by Kernon Dillon - The source link I had is no longer good:

Setting up the scene

  1. Setup the objects you’ll be using as particles.

  2. Create object groups on different layers.

  3. Create the emitter. In my case my donut glaze is my emitter.

  4. Add a Particle System - in the Object section (F7) assign a new particle system, choose Hair.
    a) Under Emission (used to be: Basic), set Amount to “0” (so that a particle will be placed/painted only when we click).
    b) Under Velocity, below Hair Dynamics (used to be: Initial velocity), Normal: “0.100”. This controls the size of your “particle instances”.

    c) In the same section below, Random: “0.030”. This is a good start value.

    d) Under Rotation, next section below, choose one that matches your settings and particles. In my case, since I needed my sesame seeds to follow the orientation of the surface of my burger bun “Normal” was the best choice.
    e) Under Render, (used to be: Visualization), choose Group. Select the name of your Group.
    f) Also in this tab, select “Pick Random”.

I don’t think the following notes still apply with today’s Blender:

Now, as far as I understand, up until now, part of the editing is done in the Object section tabs (Particle system, Physics, and Visualization), and the other part is done in the Particle Edit Properties window. Click “Free Edit” in the Particle System tab. This will show the editing tools available to do the rest of the editing.

  1. Now in the Weight Paint mode.

    a) Set the Weight to 0.
    b) Adjust “Size” and “Strength” to “1”. Strength controls the number of particles that will be painted for every click we make. Being set to “1”, our brush will paint one particle per click. We can also drag to paint many particles at a time.
    c) This one may no longer apply - With “Interpolate” you can paint particle instances that are automatically scaled to the size of the closest particle already on the emitter. This is particularly handy to fill gaps between two or more different particle sizes.

    d) This one may no longer apply - “Step”, just under Interpolate, controls the spacing of the particles.

  • To keep all our painted instances, “convert them to a mesh” by switching to “Object Mode” then going to its Editing section (F9), Modifiers tab, there you’ll find the Particles system modifier. It has a button called “convert”.

The End.

So what do you think?


Ok I made a tut and uploaded it to Youtube. Hope this will be easier for you.

Glad to help. Compositing is something I need to learn about myself. So much stuff learn. :slight_smile:

That video tutorial made it all so much easier to follow, even though you were using 2.74. It doesn’t sound like much to 2.75a, but a couple of things are not where they used to, already! But I figured their new positions anyway.

Thank you so much again for taking the time to do that Cybermonk :slight_smile:

I documented those steps in my notes. And I can move on with my project!


Tell me about!!! There’s always something new! And as if that wasn’t enough, what you had learned before now it needs relearning because that tool/procedure has been updated!
Don’t get me wrong, I love evolving and moving forward, but just catching up can be a bit too overwhelming