Help with sizing

Discussion in 'Design and Modeling' started by natholas, Mar 31, 2010.

  1. natholas
    natholas New Member
    Hello, I am new to shapeways and i would like to have a ring printed that i made, the problem is that i am using blender and there is no really clear way to know what size the object is.. since it is a ring it has to be a precise size.

    through uploading, viewing the size and then editing and uploading again i have got it to the right size but is a little confusing..

    so my question is: how accurate are the sizes that they give you on the side and are they the dimensions of the file that they send you or is it the size of the object after they mess with it to make it printable also, in the image that they give u the object is at an angle, so are the dimensions that of the object at the angle that it is in the thumbnail or is it measured in the position that they send you?

    thank you in advanced!
    ps. the object that i am talking about is this http://www.shapeways.com/model/107643/bumpy_ring.html
     
  2. iguffick
    iguffick New Member
    Blender does have units, but it does not allocate its units to a particular real life size.

    You can decide for yourself that 1 blender unit = 1 cm, or 1 blender unit = 1m. You cannot set this association in the software, you just have to remember you are working in cm, inches, metres or whatever.

    To figure out what size your model is, you can use the 'Edge Length' option in the 'Mesh Tools More' panel (when in edit mode). I tend to use a separate floating edge that I snap to any points I'm interested in. If the edge length shows 23 and you have decided to use 1 blender unit = 1cm, then the distance is 23cm.

    Beware that you can get strange results if you scale your model in object mode, then look at edge lengths in edit mode.
    You should apply transformations to get correct edge lengths shown.

    Regards,
    Ian.
     
  3. natholas
    natholas New Member
    thank you very much! i knew about the size thing but ye it doesn't give you any usable real life sizes.. what was confusing me though was the weird sizes.. i forgot to apply the scaling.. thank you!
     
  4. Calaka
    Calaka New Member
    Views.jpg Good evening

    I´m also stuck at sizing. I´m working in zbrush but I do need this 3Dprint to be a very accurate and exact size since it is for medical research purposes.

    I exported a obj. file from Osirix (from a DICOM file) to MeshLab where I deleted some unwanted artifacts and volumes. Then exported a new obj. file to zbrush were I did my modeling. Once my work is done, I try to prepare the file using the 3D printer option in zbrush but the size it shows there is too big (mm) for its real life size purpose. So I haven´t uploaded the model because I need to get the exact size to be printed.

    In the picture you can see the skull taken from DICOM file with Osirix. As notice I worked in zbrush where I modeled a part on the side. I imported the file from Osirix into zbrush to make it fit and it does as shown in the image. But the thing is how do I print this part (not the whole skull but only the modeled part) in real life sizes so it can fit the real scanned skull?

    Please could you help me out I don´t know if I have been clear enough.

    Thanks in advance



     
  5. JACANT
    JACANT Well-Known Member
  6. Fredd
    Fredd New Member
    Blender, if a object is exported as a STL, 1 blender unit is regarded as a mm by shapeways. So if you add a cube dimensions 2x2x2, shapeways will regard it as 2mm length for each edge, with a bounding box volume of 8 mm cubed.
    If you want it in cm, scale it by 10 before you export as a STL. If in inches, scale by 25.4.
    As was mentioned in the post above, model your object in BU's, then when ready to export to shapeways, scale to the dimensions you want, export the mesh