Imported models, when scaled incorrectly, are usually out by a factor of 10 in my experience, scaling up in any axis corrects this, again in my experience.
thanks Jason for the input, im learning you have to just play with it.
Curious if it is a rounding problem. If the model is coming out super small then the program exporting the file doesn’t have a unit size or the unit size is not checked prior to export. If that happens then it may come in too large or too small for PreForm.
I am wondering if it comes in so small into PreForm it loses some of the precision. Is PreForm double precision?
So far I usually make sure my unit scale is in the file’s information. If you don’t have that option in your software then maybe you have it under obj export and if so try that. When exporting obj files do not weld all verticies or merge if you have multiple mesh groups and make sure you export Triangles Only.
JasonSpiller is right. Preform was shrinking my models and asking if I wanted to use inches instead of centimeters. I modeled the piece with centimeters so Preform’s assumption was wrong and the model was imported very small. The solution was to use Maya to scale the model up by 10 and then reimport. After I did that, Preform brought in the model perfectly.
It may not be obvious, but the grid lines inside Preform are square centimeters. That can help you know if your prints are the wrong scale.
So did you find solution for exporting from 3ds max? I made model in mm in max then export as OBJ. file and then you have to scale 10 in Preform every time… Is there solution for this scaling? I mean If 3ds max is in mm and model is fitted in 14x14x17 cm (printer dim) why do I have to scale it 10 times every time? even when units are in cm you have to scale model 10 time???
When working in max make sure you are using mm (or inches or whatever) in both the display unit scale AND the system unit scale, if not you will get models that will more than likely be the wrong size.
Most modeling files have no inherent scale. They store dimension information in an ambiguous form called UNITS.
Any digital 3D file that measures 42 ‘units’ long could be 42 millimeters… or 42 miles.
Most modeling apps have a workspace in which you can set the Working Units… you can tell simply by whether its measuring tools read out in inches or cm or whatever.
The most common cause of imports coming in really small is that you modeled the file in Inches, or centimeters- and Preform’s default Units is Millimeters. So a file that should be 7 inches comes in at 7 mm.
Some apps when exporting in certain formats Can encode a units format… and sometimes scale issues can be traced to the fact that the Export dialog has a box you can set Units to… and folks don’t even look to see that its set to the same units they were modeling in.
In Preform, you can change a model’s units after import between mm and inches… but first you have to import the model, then select the model, and then pull down the edit menu to select Model Units.
If you are modeling in cm- then you’re out of luck- you will either have to go back to the original modeling app and change the working units to mm and re-export… OR in preform you will have to use the SCALE feature to scale the model by the conversion factor for the units you modeled in. e.g. if you were modeling in inches… and it came in as mm… you need to scale in all three axies by 25.4.
for 20 years now… whenever we receive a model or scan from a client, the first question is always " what Units is this in?"
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