Hi, as a test, I uploaded a solid sphere and a hollow sphere (80 percent of volume removed) . The cost for both is $63.00. How does Shapeways software check the volume when the price is displayed? Sphere 1 https://www.shapeways.com/model/613413/ec449797863599d5c05153 0f5105f6bd Sphere 2 https://www.shapeways.com/model/613415/82f45968f2517cb0a86e14 e8a60c1b62 Thanks.
Your hollow model, does it have a path from the inside to the outside? If not the software will delete internal geometry, so basically the price is for two non-hollow spheres.
^^ what Mike said ^^ A useful free tool for checking your models for volume, surface area and all other kinds of measurements is NetFabb Studio Basic (its also good for a whole host of other things too)
I put a pinhole 1/1000th of an inch in diameter in a test model. It reduced the price of the model 80 percent compared to a similar model without the pinhole. Thanks again for the suggestions.
Of course to make it printable, the hole has to be large enough to recover the powder. A 1cm radius hole should do it, though two would be better.
1cm radius may be a bit larger than necessary. I have been successful with two 2mm holes, but it really depends upon the geometry of the shape you're constructing. Shapeways is currently granting some exceptions for "Trapped Material", but they are reserving the option to change that rule in the future. A lot of that has to do with how much material is being trapped. For your sphere, you've got a LOT of trapped material inside there. Even for your model "helix04".. there might still be some trapped material, but it wouldn't be a significant percentage of the volume of the model. Remember, the point here is that they want to be able to blow pressurized air in one hole and have (most) of the material come out the other. The thing is.. they don't know what you or your customer expect to have the trapped material or not. If you don't care.. then great. But if you truly want "hollow", then they can't read your mind. Putting some holes in the model will allow the unused material to drain out. Obviously, as you increase the complexity of the model, you'll have to get more creative where you put the holes.
Why would there be trapped material in a hollow space? If it's 3D, the printing stops when the software sees air.
Few things, All of Shapeways materials use a support material to support unsupported pieces of your model. Second, for the drain hole. I can say for FUD and FD, that a small hole is fine, it will result in the build material (wax in this case) to be trapped. I don't know if the other materials require sufficient drainage as most the other materials, the support material is unfused build material, and some can be recycled.
Check out Shapeways YouTube video of WSF printing - http://youtu.be/aBNGnfoGGfQ - no air involved, just support material.