Rough fixes for 3D printed armor pieces

[Lazarus215]

Greetings everyone!

So I've come into an issue that hasn't been very easily solved... I've printed out some forearm pieces for the Centurion set, and while I though I had taken accurate measurements of my arms, and scaled everything correctly, after being printed and assembled, the insides of the armor piece are a bit narrow for my arms. I'd prefer NOT to reprint these pieces as they each eat up about half a spool of filament, and take about a day and a half to print. Not to mention all the screwing with faces and extruding them in inventor...

I was wondering if anyone else has had problems with this, and had an easier fix than taking a hole saw with the approximate diameter to the inside of the piece...

Thanks in advance!

 

[hobbitdude13]

Have you assembled the pieces? I assume you've chunked the model for build volume.
If not, then maybe model a "filler" piece that can act as a spacer between sections to expand the size without reprinting.
We'd need to see a picture to better help you.

 

[Lazarus215]

they are assembled. I was able to get them on over skin pretty easily after some initial rough cuts with a tile-cutting bit (works beautifully on plastic). But after coating them, and adding a layer for an undersuit, they were pretty hard to get on and kept falling down.

here are some pictures.
Left Forearm
looking from Elbow down
Rough work filled with clay

 

[hobbitdude13]

How thick did you print your piece to? Or is that plasti-dipped foam on the inside?
If your hard shell is that thick, You'd almost have to go in with some low-grit sandpaper and grind it down.
But if that is foam plasti-dipped padding on the inside, then you could always just redo that with a thinner foam.

 

[Lazarus215]

The original piece's walls were about 30mm thick from inside to outside. pictures are showing the clay I put it to smooth out some preliminary cutting, and was then covered with XTC-3D (a wonderful, WONDERFUL thing). I ended up going out and buying a 4" hole saw and went to town on the forearms. heres the result.

bored out
(mind the mess.) showing new fit

 

[hobbitdude13]

The original piece's walls were about 30mm thick from inside to outside. pictures are showing the clay I put it to smooth out some preliminary cutting, and was then covered with XTC-3D (a wonderful, WONDERFUL thing). I ended up going out and buying a 4" hole saw and went to town on the forearms. heres the result.

View attachment 22900bored out
View attachment 22901(mind the mess.) showing new fit

Oh wow. That's extremely thick for 3D printing, but hey you won't have to worry about strength.
But if the hole saw worked out then it's all for the good.
I only print mine to 5mm thick, and will do some thin rondoing for strength.

 

[Lazarus215]

yeah, I printed straight from the original .obj file. I used Inventor to do a negative extrusion for the holes (otherwise it would have seen solid). I get to do the same thing for the shins once I get my chest piece all modified and printed. (I included an emergency release pull tab run up to some ladder strap bindings to hold it together at the shoulders. just finished all the modelling, just need the filament to print it all)

 

[Ckesner]

Printing 30mm thick all the way around, it will cost you a fortune in filament to print and years of your life. Do you have a particular reason for printing it that thick? I know it is tempting to just take a solid file and subtract only what you think you need to fit, but maybe try doing one piece using the shell function and see how you feel about it. Your wallet, hell, your children's college fund may thank you.

 

[Lazarus215]

Considering that 1 forearm piece uses about half a spool (at 21$ a spool) yeah, it'll cost a pretty penny, but I'm really going for the massive bulky look of the armor, and between the scaling of the original .obj and my body size, the pieces are still pretty damn thick. so I either have to use the .obj with subtracted parts, or hollow the whole thing out, and try to maintain a scale where it will still look right and not be super fragile. For reference on the forearms, here are some screenshots from my slicer program.

Front-most part of Left forearm
Underside view showing thickness of the actual piece.

 

[BobasDent1138]

You could still have a high strength print if you cut that thickness down. Especially if it's a solid mesh going each layer. And if something ever breaks and you need a replacement, you can make two thinner ones for the price of one of your 30mm pieces

Sent from my SAMSUNG-SM-N910A using Tapatalk

 

[hobbitdude13]

I have to agree with Bobas on this. You can always try out a thinner-shelled piece and see if it works for you.
Depending on wear you wear the armor to, the weight might become an issue and tire you out.
You can always fill the pieces with foam to keep them fitting to your body.

 

[Lazarus215]

I'll fiddle with the models and see how much I can cut down. I'll post pictures to update

 

[Lazarus215]

in some preliminary testing, I've gotten some walls down to 5mm thickness in some spots, but it still goes up to almost 20 (probably about 17mm) in some areas. I'm gonna try a Boolean cut and see how that turns out.

New negative Extrusion

 

[hobbitdude13]

Does the program you use have a "solidify" function, like Blender?
Because the .pdos come out 2-dimensional of course, but then I usually just solidify them to 5mm, and make it an even thickness.
It's your armor after all, we aren't trying to knock your techniques man. Many paths to the same goal.

 

[shenphong]

Having a lot of the same issues and new to simplify3d. Will be keeping an eye out on this.

 

[Lazarus215]

Simplify 3D does not have a solidify function, and I was using the game-ripped .objs, so all of the pieces of armor have some substantial thickness to them.

I tried to do a Boolean cut last night and it went pretty terribly. I kept ending up with some massive holes in the mesh in multiple spots, and just couldn't seem to get the scale and difference cut to line up right. I'll try using MeshMixer, making the piece hollow, and then manually going through and editing the triangles, THEN using a solidify modifier.

Super fun stuff, this 3D modeling. makes me want to headbutt a knife.

 

[Lazarus215]

Having a lot of the same issues and new to simplify3d. Will be keeping an eye out on this.

Are you having issues with Simplify3D, or with the 3D modeling? I've got some decent experience in S3D if you need help with that.

 

[shenphong]

The actual modeling part of it and modifying the walls for a thinner print. I have a couple of printers though not keen on spending hours and hours on them for a single print due to thickness. Do you mind me asking what modeling program you use?

 

[Lazarus215]

I use a combination of programs.

For general model creation and converting .objs into workable .stls, I use AutoCAD Inventor.
If I'm doing a modification where I need to delete specific sections of mesh, I use either Netfabb (under the repair function) or AutoCAD 3DSMax.
For solidifying already 3D meshes, I'll use MeshMixer,
If solidifying a 2D object (like making a .pdo file able to be 3D printed) I use Blender (solidify modifier)

3D modeling, at least for me, is a bit of a pain in the butt... very tedious work if you're trying to fix an already existing mesh... probably just as much work as to create a new model from absolute scratch.