View Full Version : Bacteries on a surface

04-24-2007, 11:15 AM
I made an organic [not smooth] surface of many poly's.
Want to put many 1000ds of bacteries and virusses on this surface.

I tried to make surface emitter and particles 0 in size. There still seems to be a variety of space between them and the surface. They also don't get in the cracks of the surface.

Any idea how to solve this?

Thanks so much!

04-24-2007, 11:53 AM
Post a picture of what you are trying to do.

04-24-2007, 12:24 PM
Thanks for writing back.

Here is the render reference you asked for. As you can see, it is a pretty complex organic surface. You see on the bottom picture 1 bacterie. I need 1000ds of them and another 4 different type of microbes, virusses etc. All need to stick on the surface.

Using particles [using 8.5] does 2 things:
1. Particles are not accurate enough on my surface
2. they don't like to get into the cracks.



04-24-2007, 12:33 PM
HD Instance would probably be great for that, you could download the demo and see if it will work for you.

04-24-2007, 12:48 PM
I own HD instance...

However, I still will need to use the particle system of LW. They are not doing what I want.

Any idea as to how to make surface particle emitter with particles accurately being emitted?

04-24-2007, 12:55 PM
From the photo, I would probably model a low-poly surface and turn on sub-d's to get the rounded peaks and valleys. Then use mapping to create the detail rather than particles or geometry. For example, the shiny wet looking areas could probably be simulated very convincingly using a fractal texture in the specular channel, or...

If you need precise control over the placement, create a UV map and use it to paint and locate the surface detail just where you want it.

04-24-2007, 01:09 PM

Mapping won't work [you mean textured microbes I assume]. I will need to zoom in during the animation where you will be seeing the 3D microbes.

Attached you will see what I mean. This is an example file. I use the surface as emitter. Made particles all zero size and no motion. I even FROZE the object. Emitters is set to points. There is no reason why some go above the surface and some below.

Am I missing something? Hope so...


04-24-2007, 01:40 PM
if the particles don't need to move, why don't you make a point cloud object in modeler with the desired placement of the bacteria and then point clone the object onto that (in modeler as well)

04-24-2007, 01:50 PM
Sounds like you are not missing anything. In the non-frozen version, you could try jacking up the sub-division level and also play with the sub-division order to see if the accuracy improves.

Making the points in modeler as Bytehawk suggested may be the easiest solution. But if you need to use dynamics for some reason, you could try making your surface a collision surface with the event type set to "stick". Then, using a null with gravity, drop the particles from an emitter up above. After calculating when all the particles are at rest on the surface, use the final position as your starting point for the animation.

04-24-2007, 03:02 PM
Thanks so much guy's!

I made a combination of the advice from all of you and am using HDInstance for the rendering.

Now I figured out why the particles didn't lay on the surface: You need to click on "calculate" to get accurate readings! It was that simple.

Now for the advice from Bytehawk: I know how to make cloud but how can I get those points on the organic surface? Could you please discribe?



04-24-2007, 03:43 PM
I would do a faceted subdivide or more, then kill polys, points to polys. If it's to even there is a plugin called randomselect that can be found on the internet. You can use that to select random points and delete them.

04-24-2007, 05:02 PM
yep, that's the way I've done it before : subdivide like crazy, kill polys, select random points, select inverse, delete, point clone with bacteria in the BG

04-24-2007, 10:50 PM
Thanks Guys!

I did what you said but 2 questions:
1. Why point to poly's?
2. How to do point clone with bacterie in background?

04-24-2007, 11:06 PM
Please skip last questions...

It worked! Didn't do the points to poly though.

Found the random select script for free on Flay.com

All your help was really appreciated!

04-25-2007, 06:59 AM
Glad you got it sorted. And no, points to polys wasn't needed for this.