3D Printing Questions
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Here I will post questions about 3D printing. I didn't want to engulf the "Adventures in 3D Printing" thread with my ramblings. If anyone else has any technical questions, feel free to hijack the thread.
So my first question is:
Why does a model that actually uses less material cost more to 3D print?
I have two variations of a model. One is 91 cm cubed. The other is 83 cm cubed. Almost 10% less volume.
Why is it the one with less volume actually costs more to print in the same material? (ceramic).
See image. The orange one is wider but actually takes up less volume. The green one has 10% MORE volume but is 10% CHEAPER to print.
Complexity? Larger bounding box? What is causing this?
Confused.
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Good question! Larger bounding box, most likely. A model that takes up more space in the printer means less room for other models to be packed in around it.
In other cases, like Shapeways strong and flexible plastic, they give you a discount if the model fills 10% or greater of the bounding box.
Edit: This is almost always the case when using a print service where the entire build area of the printer is filled up with models, and printing supports is not a problem. For a home printer, less material almost always means a cheaper print.
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if they were made at the same time
i) I think Labor is the same
ii) more you mail, the unit weight price drops
iii) stocking of material pricing is the same as the mail, the unit price drops
iv) unit price of material colorimg can make a difference they stock more of one color than other. so the they get a better price on one then other
v) Also walk in the door shop fee is a applied to frist piece
it like buy one and get the second one 50% offIt's the billing process and it's done by a computer
the second piece is discounted
I was a TV repair man, frist tv tube is more than second
I then sell the extra tube spare for less (no extra gas and time for me to get)I don't really know myself what Shapeways does but I hope I gave you some in-site
Order both green next time
d12dozr has a good or best answer
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Thanks James and Marcus. I don't believe colour was the issue, I just painted them before I uploaded here so I could compare "orange vs green". When I uploaded to imaterialise they were both just white. I can only choose ceramic colour option from a list after uploading my model.
I think what Marcus said is probably correct, I'll double check with imaterialise what the bounding box for multiple prints is. For example, the model which takes up a wide footprint may allow only 10 prints per machine (for example) whereas the smaller green one may allow 11 or 12 prints from the same machine (for example).
I believe that unless the volume is significantly smaller, then a wider foot print model will be more expensive. I think I would have to halve the amount of material for a wider footprint model to be cheaper.
This information is not readily available though, I will have to speak to customer service.
I can't use shapeways because their range of ceramic colours is muted and limited. imaterialise ceramics are in great bold colours. Shapeways did say they may be looking at expanding the ceramic colour range though.
Food for thought!
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Oli, I used a simple test to figure out the bounding box thing...upload a model of 2 cubes and check the price on that. Using the same model, move the cubes apart so the bounding box is bigger but the volume remains the same, and the cost increases.
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GREAT idea!!
[edit]: Well I'm stumped. A model that takes up the same foot print and same bounding box using LESS material costs MORE to print. Only 3% more, but more nonetheless.
Tried working out the bounding box but can only find the ultimate largest size the print can be (340 x 240 x 200mm)
Whether this has something to do with surface area. I don't know. Perhaps increasing surface area increases paint/glaze and labour. The model with less volume has more surface area, that's the only thing I can think of!
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The airlines think this way too by charging more for some bigger people that take up more seat or floor space, but being tall is just fine.
So standard charge is based on bed floor space, the best fit for the bed is 2 x 2 or 4 x 4 and 8 x 8
and order 4, 16 and 64 that give you full fills of bed, I wonder what would happen if you don't fill the chamber. if you order fewer than bed capacity? will unit cost go upMaybe thats why airplane tickets are cheaper when you buy tickets at the last min too on un-full flight
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Great analogy James!
Unit price goes down the more you buy, depending on who you print with. You have to ask customer service for a quote though, I'll ask if it's possible to further reduce price based on filling the print beds. I don't think they'll offer any more discount though.
Some companies like shapeways offer no discount on bulk orders. They said the amount of material stays the same so they can't offer discount, which I just don't believe. Everything is cheaper the more you buy in a trade setting.
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The only other explanations I can think of is if they automatically up-charge with a higher polygon or edge count, perhaps assuming that the more complex a model is, the more possibility that it will require more time and/or labor to load it, clean it, etc.
It could also be that certain shapes require a certain printer over another, which they have a different price structure for their machines?
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Just now saw your edit from 3 days ago Oli...yes, i.materialise calculates price for ceramics based on surface area.
@unknownuser said:
Pricing for ceramics, which is $0.18/cm², is based on the surface area of your model, not on the volume of material used.
AFIK, that is the only material priced according to surface area. Shapeways charges ceramics by volume now, although they used to charge by surface area as well.
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@xiombarg said:
The only other explanations I can think of is if they automatically up-charge with a higher polygon or edge count, perhaps assuming that the more complex a model is, the more possibility that it will require more time and/or labor to load it, clean it, etc.
It could also be that certain shapes require a certain printer over another, which they have a different price structure for their machines?
Pricing at Shapeways or i.materialise is not affected by model complexity or polygon count. They typically have a set handling fee per model, then charge by volume as shown below. Each material has a different price that reflects the cost of labor and material involved. As I said in my previous post, ceramics at i.materialise is the only material that is priced differently.
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Thanks Marcus.
At least I know I'm not losing my mind now! Well that's tricky then. Going to have to look into low surface area to volume ratio.
I knew this surface area was a problem because my model prices in stainless steel kept going down but the ceramics kept staying the same even though my volume decreased. When I decrease volume by making 'holes' and gaps, the surface area increases dramatically.
Ceramics is still cheapest and best material for me though.I wish there was a plugin where I could just click "Entity Info" on the group and then just change the "surface area" or "volume" and the group will scale accordingly to these new values. It would be great for 3D printing! I would also like an imaterialise plugin where you just right-click a solid and it comes up with prices in all the materials.
Looks like I'll need to make ceramic version and steel version of the same model, so I'll have to make the ceramic ones simpler whereas the steel can be more intricate to decrease volume. Ceramic is charged by surface area because the glazing costs more than the actual printing material.
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There was a imaterialise SU plugin that was offered a couple of years ago, but I never tried it and I haven't seen anything about it since.
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i.materialise plugin is available here, but it just uploads the model to their site. To get the price you still have to upload it.
Oli, I agree a plugin to get the pricing right inside of Sketchup would be awesome.
I know both Shapeways and i.materialise have API's that allow developers to access that info. Gonna have to learn Ruby or talk to one of our plugin gurus! 
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What about the Uniform Scale based on Volume? Or Uniform Scale based on Surface Area?
Is this possible with current plugins? I'll write a plugin idea in the plugin forum if not. I know you can do this manually but that's not the point.
Say you have a model that is 30cm cubed and it must be 28cm cubed, you could just type this in and the grouped solid scales down uniformly to achieve the desired volume.
@d12dozr said:
or talk to one of our plugin gurus!
that sounds more appealing haha
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I was going to ask TIG about this, but he's already done it!
Scale by volume plugin!
http://sketchucation.com/forums/viewtopic.php?p=493763#p493763
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