- HO scale – 3.132″
- O scale – 1.738″
- 1:24 – 0.864″
- In HO scale this cube would be 0.138″ x 0.138″ x 0.138″ with a 0.012″ hole
- In O scale this cube would be 0.250″ x 0.250″ x 0.250″ with a 0.021″ hole
- In 1:24 scale this cube would be 0.5″ x 0.5″ x 0.5″ with a 0.042″ hole
- In HO that 0.138″ is 3.5mm (ok .. 3.5052 but .. that extra bit is not worth worrying about)
- In O that 0.250″ is 6.35mm
- In 1:24 that 0.5″ is 12.7mm
- In HO the cube is 3.5 x 3.5 x 3.5 with a 0.3 hole
- In O the cube is 6.35 x 6.35 x 6.35 with a 0.533 hole
- In 1:24 the cube is 12.7 x 12.7 x 12.7 with a 1.07 hole
— History —
Sketchup was created by @Last Software with version 1 released in 2000 as a modeling tool for “Architects, designers, and filmmakers”. The part about ‘Architects’ may have something to do with a couple of the problematic issues with the program – at least as far as it relates to those of us using the program to model scale objects.
— Problem —
The program refuses to create a radius below approximately .018″ – which means the smallest hole you can create therefore is .036″. To give an idea what this means .. here is what that .036″ is in various scales:
Obviously, those of us who use Sketchup for scale modeling will have a problem with this.
This same restriction comes into play when re-sizing objects as you can get glitches where you have missing polygons when resizing curves. Sketchup can throw a fit sometimes when resizing a spherical surface.
So .. what to do?
One way would be to re-size a model up x 100 .. and then re-size back down x 100 when finished. This can work .. probably works *most* of the time but not all. You can still run into problems when that reduction re-size drops radii below that 0.018″ radius.
— Pmm —
My own solution is to use what I term .. Pseudo Millimeter .. Pmm modeling.
Ummmm. How to explain so it makes sense .. let’s try this …
Let’s take a cube which full-size is 1ft x 1ft x 1ft. We also want to punch a 1″ dia hole though it
sooo .. back to the cubes …
Ignore the ” .. indicating inches .. or simply uncheck the [ ] Display units format in Model Info.
Happy days .. that 0.036″ minimum hole dia is now .. ummm .. 0.00014″
|If I design a cube 25.4 mm on a side and export as a DAE file, I can then import it into MeshLab do what 3D stuff I need to do and export a STL file which will contain a cube 25.4 UNITS on a side. I upload to Shapeways and simply tell them that the model is in millimeters .. and the model is exactly the size I need it to be.|