How to deal with specific geometrical constraint and non-flat surfaces

[benedettafrida]

Hi all,

I need to start saying that I am really new to 3d graphics in general and to Maya...  
I am a PhD student in computational neuroscience and lately I am getting more and more interested in the 3d modelling world. The idea of mix art and science…is too tempting.
I’m trying to build a 3d model of a piece of neuron with all that it’s inside it using data from imaging experiments.

All of this for saying that I am “force” to use specific geometrical constraint. 

Long story short, I have polygon, (egg shaped, but really irregular) empty inside, and on the upper half of it, facing the inside of the polygon, I need to insert little objects (cylinder like) with a specific density. Every cylinder has to be distant from the next one of 134 ± 28 units. These cylinders also need to be parallel to the normal of the face they are inserted in. I can’t find a way to specify all of these together. 

I try to modify the polygon in order to have all the vertices at equal distance but of course, the geometry felt apart. 
I also try to use LT_tools: using it I am able to correctly position the cylinder (following the normal) but again I can’t find a way to get the spatial distribution (the equidistant function doesn’t work for me). 
Last week I got the idea of use the n-Cloth function: starting from a polyplane formed by quads with edges length of 134 units I had inserted a cylinder per vertex (so I got the right distance between them). Then I created the n-cloth for the polyplane and a passive collider for the “egg” and let it fall over…. I don’t know why, but every times I can see the plane slide on one side of the egg, create a little bump but then literally fly away and fluctuate in the air.. 

Any idea of how I could do it guys? Do you know how to specify a mean distance between neighbours object on a non-flat surface? Do you maybe know why my n-cloth doesn’t work? Thanks so much in advance for all the possible help. 

Frida

PS: doing it manually is something not really possible since the number of cylinders to insert is something like 300 cylinders.  Last, for sake of clarity a Maya 2011 binary with the “egg,” 2 “cylinders” can be found here

[joojaa]

This is a nontrivial issue. Lets just say wrapping cloth is not going to cut it. I would start with a dodecahedra, then pull points in a iteration towards the desired shape. Then smooth, iterate smooth. Bit really this really depends on the desired pattern.

PS: doing it manually is something not really possible

How do you think programmers come about to doing the code then? Prerequisite for doing anything is being able to do it manually. That is how you do it, manually in small scale until you think you get the general idea then do it within a loop. Thsi si why doing it manually is indeed possible, if not a must for developping the skill to do it.

PS: you will find that very few basic maya user has ever done this. Its definitely nothing extremely simple, but you are a scientist whipping up a adaptive fourth order Rudge-Kutta algorithm with associated calculus should be up your alley, right.

PPS: maybe your platform of choice should be houdini.

IMPORTANT WARNING: please dont ever give out your data in binary maya files, not only does that lead to compatibility issues. Which means smaller audience, not only that but a ascii file could be opened in very old mayas aswell so your also making your potenttial crowd even muc smaller still.

But lets just say maya binaries are very good attack vectors. Mayas a macrofile that can do ANYTHING wth your use priviligies on the machine. So i wouldnt open maya binary files from untrusted sources even if you paid me to do so. If i wanted to PWN you thats how id do it, not many antiviruses would see it comming.

[benedettafrida]

Hi Jooja,

Thanks for the reply.

“would start with a dodecahedra, then pull points in a iteration towards the desired shape. Then smooth, iterate smooth. Bit really this really depends on the desired pattern.
”

Could you please elaborate a bit more? I’m not following, sorry.

“>> PS: doing it manually is something not really possible

How do you think programmers come about to doing the code then? Prerequisite for doing anything is being able to do it manually. That is how you do it, manually in small scale until you think you get the general idea then do it within a loop. Thsi si why doing it manually is indeed possible, if not a must for developping the skill to do it.
”

Yes sure, that’s what I meant. I’m just scared that the “quickest” solution to my problem will be doing EVERYTHING manually, with no coding involved!! That will be a nightmare!

PS: really sorry about the binary issue. Didn’t think about it at all! Ops! How about some pictures?

PPS: why Houdini?

Thanks again.