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Building a shell on a thin stl import

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I am new and have chosen 3d coat to try and do a specific thing: I have imported an stl of a skull into voxels. What I would like to do is fill the interior spaces to study and extract them (ultimately with 3d printing). I have tried subtracting it from a cube but the is too much exterior material to try and remove without damaging the interior forms. Ideally I'd like to add to the surface thick enough to cover the cube. I have tried clay, extrude, etc in Voxels but it distorts the interior spaces of the skull. I have also tried extruding and building in Surface but I still get distortion and it has trouble revoxelizing. I am sure there is a simpler way to do this but I need some suggestions. Any ideas?

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th_ScreenShot2012-10-24at90223PM.png?t=1351136493tth_ScreenShot2012-10-24at90323PM.png?t=1351136489

complete image & cross-section

Thanks but that didn't do anything. The file is an stl from a scan of a real skull. It is a closed form with many voids, many of which interconnect to exterior openings. I'd like to apply a thick shell that conformed to the exterior (exactly) as well as covered the orifices. Filling it exactly would work too because then I could subtract the stl from the solid form. any other thoughts?

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Sorry, I'm getting confused as to whether you want to FILL the inner volume or create a SHELL (thickness). I find that whenever I request a feature from Andrew, if it's even remotely complicated, I will record a screen capture and try to show what I am asking, so there is no confusion. Try Jing. It's a free screen recording app and provides free video hosting (screencast.com). Maybe create a Voxel object from a primitive, ensuring it has enough resolution to capture all the small details you want. Then merge your scanned mesh, positioning the temporary proxy within the Voxel object. You can hold CTRL + SHIFT while clicking APPLY or the ENTER key. This will create an intersection volume, as you can see here.

Again, I have no idea what you are trying to achieve without some further clarity. If you want to create just a shell, you can right click the layer and choose EXTRACT SKIN > HULL FROM Voxels/Surface

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Sculpt a new voxel following the stl perimeter with layer density [2x] or more

* make it a little small in size than the original one

When done:

Select the original stl... RMB > Substract from the new voxel sculpt

Interior spaces must appear

I tried it with a small prototype... but your stl is very high

hope this help

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carlosa- thanks but that didn't do the trick, my skull file, while solid has too many interior spaces and they would intersect.

AbnRanger- thanks for the info on Jing! As you can see from my attached screenshot( a cross section for clarity) that I can do as you suggested but the problem is all the time it would take to mine out the interior forms. I tried doing this but it was very labor intensive and I often marred the structure I was trying to get. I only want to make the interior spaces positive- think filling a skull with a material and they removing all the bone. I only want the spaces that once held soft tissue (very halloween!) My idea was to add a greater thickness to the exterior thus giving more room to place my voxel object made from a primitive. This didn't seem to work because whenever I tried to add material to the exterior of the skull it distorted the interior spaces. Another idea was to make a solid voxel primitive that was exactly (or just slightly smaller) than my stl and doing the same "subtract from" with layers but I can't figure out a good way to make it exact. I am thinking that the orifices on the skull (nasal cavity, brain stem opening, etc) are making this even trickier? I could probably go into Rhino and close them if that would help. I don't know if then the "Fill voids" command would work?ScreenShot2012-10-25at41541PM.png

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is the model file size big ?

will you attach it here ?

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Ok, I think this it what you mean, you want to fill where the brains,eyes and soft material use to be but also fill the orifices as well.

You want at the same type not effect the external part of the skull.

There is a way that will not effect the outer part of the skull, It does require some manual work but it is workable.

I did not use a primtive but used the voxlayer command to create the fill material. I made the thickness quite large This will help close the openings in the skull.

The voxlayer command will put the created voxel object on it's own layer.

Next I used the transform gizmo to make the voxlayer object smaller to where I could see to work on it. Since the voxlayer was created off the external part of the skull, this gave me a good starting point. I then I just starting working away at it to form around the skull.

Once done merge the two layers.

Used the fill void command under the voxtree layer.

fixed up some spots on the final mesh.

Yours is more complicated of course so whether is is worth the effort only you could decide.

In the end you could extract a thin shell of the finished work since your model is solid on the inside using the extract skin feature under the voxtree command.

3 pictures.

The first shows the hollow skull and the skull after filling plus some manual work. Yours has some internal material but that does not matter in the method I worked on.

2nd picture shows the merge layers with the skull and openings filled but the external part of the skull was not effected doing the course of the work.

Last picture shows the fill material in white prior to working on it. The dark brown color is the voxlayer mask before I removed it.

Now this might not be what you want at all or maybe sorta, kinda what you want... ;)

3DCoat has no designed tools for this but, I thought I take it as a problem to solve. I learned a more things I could do in 3DCoat..

post-518-0-04718400-1351221086_thumb.jpe

post-518-0-90367500-1351221178_thumb.jpe

post-518-0-94545600-1351222294_thumb.png

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Ok...I think I may have a solution here. If you indeed have lots of voids within the model, then take these steps:

1) Click on the DUPLICATE LAYER icon at the bottom of the Vox Tree Layer Panel

2) Right click the original object's layer > Fill Voids

3) Hold the CTRL key while dragging the copy layer onto the original (this will use the copy as a cutter)

http://www.screencast.com/t/y6UKdzsrK9

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Andrew should be back from vacation soon, so send a request to: support@3d-coat.com

There isn't much of a need for this function in sculpting/modeling, so that's probably why there isn't a tool that does that. But I think Andrew could accomodate the request without a lot coding. It would essentially FILL VOIDS + REMOVE CURRENT VOLUME.

Amen to that tool added to 3DCoat. The method I used worked but I would not want to do a boat of load complicated scan files that way... :wacko:

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Aarg!

AbnRanger- I closed all the exterior holes and followed your directions but it would not work! I thought maybe I hadn't closed the form so I also did the process with a small section (capped with a primitive) and still no luck. Could the difference from yours be that it was not made in voxels, merely imported?

Sigh! I have spent way too many hours on this... I think it might be time to give up.. gulp!

Thanks for all your help everyone!

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Aarg!

AbnRanger- I closed all the exterior holes and followed your directions but it would not work! I thought maybe I hadn't closed the form so I also did the process with a small section (capped with a primitive) and still no luck. Could the difference from yours be that it was not made in voxels, merely imported?

Sigh! I have spent way too many hours on this... I think it might be time to give up.. gulp!

Thanks for all your help everyone!

Are your layers in Voxel mode? They need to be. When you merge the model in, uncheck "MERGE WITHOUT VOXELIZING" in the tool options panel. You create a duplicate copy of the scanned mesh (with all the inner voids and such). One of those you want to fill (voids). CTRL + Drag the original (with holes in it) layer onto the one that has been filled....or you could right click the layer and choose SUBTRACT. Again, it will act as a cutter. Can you screen record (with Jing) your process, so we can see indeed what is going on in your scene? Could be something small (usually is, it seems).

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well... i downloaded the .stl just to try substract

- fill voids in voxel mode or fill holes in surface mode dont solidify the object... just fill some holes in a random way but not fill all.

- thin shell use the inner and outer geometry

- autotopo try to retopo inner and outer geometry too

at this point the only way is manual retopo, and use the exported .obj for substract

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AbnRanger- here is a Jing video- http://www.screencast.com/t/06vh6YTWf I was worried that small exterior holes might be messing things up so I cut off a small portion and capped it with a primitive. You can see, as Carlosa mentioned, if fills a few random bits but not the whole thing.

When you merged that model in, if there were internal voids, that technique should reveal only those voids.

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When you merged that model in, if there were internal voids, that technique should reveal only those voids.

When you merge into the Voxel room, you can check "Merge to Separate Volumes." Maybe some of those internal objects will come in as separate layers/objects.

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