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Author Topic: Shelling photoscans  (Read 19942 times)

igor73

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Shelling photoscans
« on: February 13, 2014, 01:46:38 PM »
Hi,

I need to shell (hollow out) a few photosscanned models for 3d print.  The prints would be to expensive solid. One is a scan of a 10.000 year old skull and the other is cannon. Images captured under water.  The models are very detailed.  Around 1 millon faces.  The skull have many small extrusions and the cannon large nr of small details. 

I use Blender for modeling. Normally the solidify command works very well on hand modelled meshes.  But not on these.  There are details that are smaller then 1mm and if i set the thickness to anything more then 1mm lots of artifacts are introduced.  As these are archeological artifacts they need to be exact and not deformed in any way.  I need a wall thickness of 2-3mm. 

So i have tried Meshlab using the uniform mesh resampling filter.  This almost works but not quite yet. 

Are there any software that would work for me?  I have Netflabb basic but that does not have the shell feature.  The Pro version is 1500USD.  If it works it would be worth the money but with no trial version i am hesitating to buy it.  Lot of money wasted if it does not work. 

So have anyone tried Netflabb Pro on complex models with small details and found it worked?  Any other software that can do the trick? 

If anyone would like to help i could send you the files and you can have a go with them. Would be great if someone that has Netflabb pro could try if the shell command works on my models.  If so i can buy it without remorse. 




Wishgranter

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Re: Shelling photoscans
« Reply #1 on: February 13, 2014, 03:18:16 PM »
Hi Igor73

just send it to muzeumhb@gmail.com, can help with it, im dealing with hollowing on daily basis.....
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chrisd

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Re: Shelling photoscans
« Reply #2 on: February 13, 2014, 06:06:31 PM »
I bought Netfabb Pro, and shelling does work very well.

You can also set the accuracy of the shell. So if you have a lot of surface variation, it can simplify the inside surface based on an amount that you choose.


FoodMan

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Re: Shelling photoscans
« Reply #3 on: February 13, 2014, 07:28:57 PM »
or.... at $375 you have

http://3d-coat.com/

it works very well for shelling as well.. import you model as voxel, shell it.. re-export your model as obj or fbx

voila 8)

chrisd

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Re: Shelling photoscans
« Reply #4 on: February 13, 2014, 09:38:37 PM »
That is good to know.

I've considered buying 3dcoat for the voxel functions, but I have been waiting to see how ZBrush moves along in this area since I already have a license. ZBrush calls their counterpart to voxels "Dynamesh" and while its not the same thing, there is some crossover in capability.

I think that when ZBrush goes 64 bit, the relatively low Dynamesh resolution will go up quite a bit.

igor73

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Re: Shelling photoscans
« Reply #5 on: February 13, 2014, 09:51:20 PM »
Wishgranter,  thank you so much for offering assistance!.  Greatly appreciated.  I have been pulling my hair on this matter for a few days.   I will email  a download link.

 I would really like to know for future project how to do this though.   What software are you using? 

Netfabb also has a private version for only 300USD that has the shell function. Do you guys think it has the functions i need?   I am mainly after the shell function. 

 Chris D,  Do you think Netfabb could generate a shell for the attached model?   It is a picture  of an actual print that was printed solid.  I am worried it will go wrong on the small details such as the wooden branches and encrustations on the cannon. 

Does Netfabb destroy the UV mapping or is it kept intact?  I like to print in color so keeping the textures intact is important.  Pros- Cons 3d -coat vs Netfabb? 


chadfx

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Re: Shelling photoscans
« Reply #6 on: February 13, 2014, 10:08:18 PM »
I wound up using Mudbox to do some crude shelling by scaling down a smoother lores mesh and roughly shaping it to fit the irregular shapes I was printing. So I could leave some delicate parts more (or completely) solid, while still removing most of the main volume. I think I used Meshlab to do the boolean subtraction. Not the most precise method, but still saved quite a bit on the printing costs.

I haven't used Blender much, but possibly it's modelling tools would allow you to use a similar methodology.

Earlier I had tried using some filtering and other procedural recommendations all inside Meshlab, but it kept crashing and was difficult to predict how well it would work.

Cheers, -C

igor73

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Re: Shelling photoscans
« Reply #7 on: February 13, 2014, 10:20:57 PM »
Stupid question from me about 3d coat vs Netflabb.  I did not realize that 3d coat was a full blown modeling program.  Checked out the video.  Looks like really interesting modeling tools!.  Will investigate further.  I do need a very fast and efficient method and i have already spent a lot of time learning Blender for my modeling needs.  Maybe the Netfabb approach seems easier?.  Just drag a few slider and then done'?
« Last Edit: February 13, 2014, 10:32:45 PM by igor73 »

Wishgranter

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Re: Shelling photoscans
« Reply #8 on: February 14, 2014, 12:45:03 AM »
Hi Igor, im uploading results, but need a bit Q/A

Depend on what need to model, or clean up models, when need cleanup, its much better to use ZBRUSH......
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igor73

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Re: Shelling photoscans
« Reply #9 on: February 14, 2014, 01:12:19 AM »
Great news.  Looking forward to the result!    The skull had some disconnected faces.  What do your ever to with clean up?  Non manifold faces or just general cleanup such as removing disconnected faces and artifacts?   Guess i could do clean up pretty well with Blender and shell generation in Netfabb?

Are you you using Z brush for the entire workflow?  Obviously you  know this better then me so i am very interested in your opinions.  It is important to me to keep the work flow simple and time effective.Z brush is 795USD to.The private version of Netfabb 300 USD. 

 

Wishgranter

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Re: Shelling photoscans
« Reply #10 on: February 14, 2014, 01:17:27 AM »
Yes the Zbrush is much better for this sort of work..... see the email please....
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chrisd

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Re: Shelling photoscans
« Reply #11 on: February 14, 2014, 03:29:29 AM »
Netfabb also has a private version for only 300USD that has the shell function. Do you guys think it has the functions i need?   I am mainly after the shell function. 

Chris D,  Do you think Netfabb could generate a shell for the attached model?   

Does Netfabb destroy the UV mapping or is it kept intact?

I have not used the Netfabb private version so I can't comment there. The shelling on the "Pro" version should handle the detail like the wooden branches and encrustations.

If the thickness of the shell exceeds the minimum dimensions of the detail, then the detail just gets filled in. (This is where other tools have problems, because the shelling can create intersecting surfaces.)

Any operation that adds or deletes vertices is going to destroy the UV's. This is true for any app. However some apps allow you to take the UV map from the original model and reproject it on the modified version. Unfortunately, Netfabb does not do this, at least in version 4, which I have. I don't know about version 5 ...?

I have seen some demos using Blender that show how to do this, but they used an open surface in both cases. I don't know how it would handle projecting it from a open surface to a shelled solid.

You would still need a modeling app in addition to Netfabb.

igor73

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Re: Shelling photoscans
« Reply #12 on: February 14, 2014, 04:02:32 AM »
"Any operation that adds or deletes vertices is going to destroy the UV's. This is true for any app. However some apps allow you to take the UV map from the original model and reproject it on the modified version"

It should be possible to import the UV map exported by Photoscan i think.  When using obj files this is handled automatic in blender.  I have no idea if netfab messes this up.  Anyone know?  99%  of the time i will hollow out closed models.  Then this should not be a problen right?  The skull was a special case.   Don?t expect to run in to many of those type of objects. 


chrisd

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Re: Shelling photoscans
« Reply #13 on: February 14, 2014, 08:30:20 AM »
Netfabb v4 does not keep texture information, UVs, or vertex colors. I don't know if they have added support for this this in v5, but with the demand for 3d printing texture, it would be useful.

However, the downside to adding ability to use the color info now, in my understanding, is that 3d printing in color currently is not using ANY standard for how the color is defined. I don't believe it is possible to make one color file that will print on every color 3d printer without conversion to a different format on some systems.
 

FoodMan

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Re: Shelling photoscans
« Reply #14 on: February 14, 2014, 12:01:33 PM »
yes in 3D coat, after voxelization, UV are destroyed... but it's not a problem... you just re-import the Hollowed model in Pscan and redo a texturing.. voila..  ;)