3D Printing Group

I think the "inflation" you talk about might be an optical effect that catches out a lot of people. The solid chunk of VeroClear with a curved outer surface acts as a lens, so everything inside it looks bigger than it really is. Neither the game nor GrabCAD Print has a full optical simulation tool, so you can't see the effect there, and of course if the model was designed to look right in the game (with no lensing, or with a thin glass layer), it'll look wrong in the real world (with lensing).

I expect that if you stop the print halfway through, so you can see a cross-section of the part, you'll see that the baby looks normal size on the exposed side, and too big on the side that has the VeroClear.

It's quite hard to design to compensate for the lensing, so I'm afraid I don't have any tips for that. You might get better results if you separate it to two parts: one with the opaque parts, and empty space around the baby, and a second part which is just a thin shell of VeroClear. Once you've polished the transparent part, you can stick the two together. Because the VeroClear would be a thin shell, the lensing will be much less.

Edi, first of all- what an amazing print! I work at GrabCAD/Stratasys along with Dan, and I wanted to offer- stopping a test print halfway is a good way to troubleshoot the issue as he mentioned, but you could also send me the file and we have a special secret tool which can look at the print slice by slice, to see if the 'puffiness' is real or an illusion! I talk about the tool here in my tutorial about printing with clear + texture: https://grabcad.com/tutorials/how-to-control-the-transparency-of-your-3d-printed-parts-the-hardest-task-yet and my email is shuvom@grabcad.com. If you send me the .print file, or a ziped up version of the full VRML/OBJ, I can take a look inside and see if there is an issue! (Typically, when I see 'puffiness' inside a clear print, it's because the thing inside was made in a program like Zbrush or Blender, and has some watertightness issues with its triangles. Because there's a small hole in the surfaces, the slicer can't tell what's 'inside' and what's 'outside'. But usually that puffiness looks a LOT worse than what you've got here.) You can try a repair in GrabCAD Print or Magics to see if that changes things, and the stop-print-halfway, but if you want more diagnostics after that, please email me at shuvom@grabcad.com and I'll help you out!

That's not the case, I got another clear+fullcolor couple with the same issue, the cube is flat and no distortion will be caused:

Here's the orignal design and you'll know it's definitely not the lighting issue:

While there's another normal print:

The circled part is a perfect print I'm expecting :)

Wow hi Shuvom! This is really a responsive community! I'll send you the files soon :) Thanks again for your prompt reply!

Just emailed you :) Please check it for me when you have time, thanks a lot!

Just sent back a reply, with pictures. I think the fix is two-fold: use the auto repair tool in GrabCAD Print to get rid of small model errors (which cause the slicer to not know where the inside is), and use 'Part Priority' to make sure the baby prints instead of the clear shell. Look over the two emails I've sent, and let me know how it goes!

Here's a quick summary:

Thanks Shuvom! We will test again according to your instruction and let you know how it turns out :)

Edi,

Great! I've actually learned more about this issue over the weekend, from one of my co-workers. What's going on is when the slicer has a body it can't find the inside and outside of (the body is not watertight, which happens often in complex models like the baby), it makes a conservative assumption and applies the color layer to BOTH sides of the surface, just in case. This extra 1-1.5 mm of color is what's making the baby and your wedding couple look puffed up. This only happens if the body is not watertight AND it is encased inside another body.

The repair of the baby body in GrabCAD might have fixed it, but if not, the answer would be to go back to the software that generated the baby and make sure it is watertight there. There is also the possibility for you to do a forced boolean of baby and clear shell, as a last resort.

Let me know how it turns out, and we can go from there!

Hi Shuvom, our techician took your instructions and it worked like a charm! Now we got the perfect cute little baby and wedding couple, yay!

Edi, great to hear! What I learned from this was:

• The puffy mainly happens when a non-watertight group of surfaces is inside another body
• The symptom is the color printing both inside AND outside of the non-watertight surfaces, making it 1-1.5 mm thicker than desired.
• Best fix is to make sure the interior body is watertight in the sending program
• As a smaller fix, you can 'Repair' the body in GrabCAD Print and
• Also set the 'Priorities' of the body, so that the interior body is set to print instead of the interfering outside body.
• But making the bodies watertight in the first place is a much more stable fix.

Glad this worked, keep us updated on your other cool prints!