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3d printing, hollowing model, shell, interior wall for 3d printing

ZBrush Usage Questions
#1

I am trying to hollow out my model to make 3d printing cheaper. Below is what i have tried. But i know there is a way to make an interior wall with a uniform width all throughout the interior. - But maybe not in zbrush.

Attempts at hollowing:

WAY1:subtract boolean
WAY2:manually
WAY3:extract
WAY4:re-topography

here is a link to the full conversation i had about hollowing a model. look 3/4 down – shanec102— for full descriptions of how i tried to hollow:

http://www.shapeways.com/forum/index.php?t=msg&goto=22371&&srch=zbrush+hollowing#msg_22371

attached is a photo of a perfect uniform wall.

my question is how do i do that? If I can not do it in zbrush, what software do i need? – hopefully it is free, or at least under 1000k.

As I have found little on this topic in the forums any help would be appreciated,
shane

Attachments

humancrosssection22020.jpg

#2

extract.JPG

#3

Thanks for your reply,

Extracting puffs out the model. So if you are doing portraits this will screw up allot of your detail. The bigger the extracted thickness the more distortion.

I do not know how to extract so the distorted wall goes inward.

What i have done is make the extracting process part of my sculpting process. What i mean is. i extract before i am finished sculpting. I extract when my model is still a bit general looking. Then after the extraction i sculpt (only add) on to the surface wall. You cant really subtractive sculpt, as you will crush your wall in. This severely effects the sculptures i can do.

Is there another way to build an interior wall that wont effect the exterior wall?

#4

If you set Extract --> thick to -1 it will project the walls inwardly.

I had a play with the demo head this morning. I needed to smooth the projection. Then if I used a small enough dia. zproject brush, I was able to transfer detail back onto the outer skin of the shell.

Software to shell out organic forms does not come cheap (I’ve been quoted around the £10k mark before now!). I think the software provided with some RP machines, does do this realatively quickly and easily (but would you want to buy a machine?). Certain RP processes are worse than others for cost. In my exp. Z-Corp seem to be the most forgiving regarding wall thickness costs.

#5

Further to my earlier comment - Perhaps if you built the model using a z-sphere base you could skin the original sheres to give a cavity inside your model. It wont give an even wall thickness, but it will help with costs.

I guess you have to weigh up how much time it will take you to model a perfect skin (i.e. your time costs) vs the extra RP material costs!

Depending on the shape… maybe try to clone your model and if possible scale it down to form the inner cavity.

#6

Another point sprang to mind…

I did some test models with an FDM machine reseller a couple of years back… the software that was provided with the machine (Dimension) was able to do a hollow fill option at a click of a button! It created a honeycomb interior to the model. Worth looking into…