Hollow impossible heart

by mowi, published

Hollow impossible heart by mowi Oct 21, 2012

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This is a hollow version of the impossible heart, or actually 2 versions. I needed one for a wedding gift. Off course the happy couple wanted some financial support for their honeymoon. But I have to much pride to give them just an envelope. So we decided they would have work for it. We put the money inside the heart. It took them a while to figure it out how to open it ;)


I made one entirely hollow heart and one with walls. The one that is entirely hollow can only be printed with support. I found it was difficult to put it together with the money inside so I made another version which had inside walls. Now I could stuck the money in the separate parts.

You can use the openscad file to make your own versions. The hole in the middle is made with a scaled down version of the original shape. So a hollow Cube, Sphere and Heart will work. But for example a donut would not work. In the openscad file the size_hole_inside reflects how big the inside hollow shape is. You can use it to change the outside wall thickness. When it is 1 the hole is the same size as the whole product so you would not get an outside wall. If you do not want inside walls you set "withwalls" to false. The wall thickness is the thickness for the inside walls. I also put some code in the comments which put a B and a P in pieces 1 and 2. I included a P and a B stl, so if you happen to need a P and B you can make your own STLs for the heart-pieces.

The STLs for the heart-pieces are without letters.

For the STLs the one with walls is bigger as the one completely hollow.

I printed them on a Prusa mendel. After removing some small irregularities on the edges they fitted very well.

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Could you please describe how can I add letters on the heart?

Is the size of the one with walls smaller than the one without?

how do i re-open it?

Do I need to make my own heart.stl file? I see it must be loaded in SCAD, which I use but have little experience with. When I Complile the SCAD file it makes a rectangular shape...


HI Theuns, Off course you do not have to make your own heart.stl. Its is
the exploitable heart from emmet. http://www.thingiverse.com/thing:6190http://www.thingiverse.com/thi... . I am sorry that it wasn't clear. Good luck!!

Exploitable Heart
by emmett

What size do you recommend making this?

Depends on your printer and what you want to put in there. I printed it at 100%. It has thick walls so I got multiple perimeters for my 0,5mm nozzle. I had to fold the money pretty small to get it in there. The endresult is about tennisball size. If I would print it again I would probably change the scad file to get thinner walls.

i can't put it together ? whats the trick i can get three out of the 4
pieces but can't get the last piece in

Hi Dynamic, It is a bit complicated, I would make a video but I haven't got the heart here at the moment. The trick is to slide the three parts apart again. At some point you can slide the 4th one in. Then you will have the heart like it is in the picture and you can slide it together by pushing on two opposite parts alternatly. It would probably help if you have one hand more. I found the pieces with walls are easier to put together because you have more to hold on to. I'll see if I can make a video later this week.


thats pretty cool design, but are you sure they just didnt take a hammer to it to get to the cash?  if I were you, I would ask to see the original heart. also check for signs of glue.


 I had a close look on them while they were trying to open it, not surprisingly the Bride figured it out first ;)