correction for pricing FAQ

Discussion in 'Bug Reporting' started by dadrummond, Dec 1, 2009.

  1. dadrummond
    dadrummond Member
    The current pricing FAQ says:

    "How is your pricing calculated?
    Our pricing is based upon the actual amount of material used in your model. So the actual volume of your finished object not the volume of the bounding box. The model detail page has the pricing of each model on it. All prices include shipping and handling."

    The first sentence is not true. The pricing, at present, is based on the predicted amount of material, based on the sum of the volumes of all objects in your model. This predicted amount can, in principle, deviate wildly from the actual amount of material used, because objects can overlap arbitrarily, leading to double-counting of volume. In other words, the sum of the volumes (upon which pricing is based) is larger than or equal to the actual volume of material used when printing a model.

    The FAQ should be updated, preferably with the second sentence of the above paragraph.

    I think it would also be extremely valuable for some talented member of the Shapeways community to develop an algorithm that better approximates what SW wants, which is the actual volume of material that will be consumed during printing.
  2. joris
    joris New Member
    Technically you may be correct although I would tend to dispute arbitrarily. But, I don't want to confuse people on the FAQ. I also don't want to be dishonest though. Up and until now I thought that the volume calculation was very accurate?

    There were a few miscalculations with overlaps and such but I thought it was ok?
  3. dadrummond
    dadrummond Member
    Personally, I have modeled connections between objects in my models entirely by overlapping them. I knew (by reading extensively on the site) that I would be charged for the overlapping volumes.

    If SW has implemented a proper correction for overlapping volumes, then I stand corrected. Otherwise, I think the site should be upfront about the way pricing is calculated.

    Right now, I believe I could create two overlapping 1cm^3 cubes, with an apparent volume of 1cm^3, and be charged (close to) $20 for printing them in stainless steel -- double the actual price of the material used. Three overlapping cubes would be charged triple. Etc. -- hence the word "arbitrarily". If this isn't true, then I'm misinformed. And I'm terribly sorry! Please let me (us) know. I was simply perusing the FAQ and noticed something that I thought was inaccurate.

    If SW has solved the overlapping-volumes problem (which would seem to involve a rather sophisticated Boolean algorithm), it would be useful if SW would share a script (similar to the Blender Shapeways Calculator by Loonsbury) that calculated the actual volume, not the sum of the volumes of the objects in a model.