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Sketchup trick for small items Dream and design
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Prolific poster 3,069 posts DKRickman Prolific poster 3,069 posts
DKRickman

If you've ever tried to draw something in Sketchup and wanted to use actual instead of scale dimensions, you'll know that it doesn't like really working with our small subjects.  Specifically, I've found that it doesn't allow you to draw a 1mm radius arc, or circles much smaller than that, and it will not properly extrude small objects (like HO 33" wheel treads) around a circle.  I've even had trouble making 3/8" diameter spheres.

When I draw in 2D, I frequently use scale dimensions, but the main reason I like drawing in 3D is to visualize how parts will fit together and check clearances.  I also figure that if I ever come up with something I'd like to have printed, the drawing is already the right size.

While it won't create the objects, it will display them if they're already part of a drawing.  How do you make it part of a drawing if you can't draw it?  Scale it!  I draw small objects much larger, and then scale it down.

I find that metric is great for measuring small parts, especially since I have cheap calipers which read down to a tenth of a millimeter or 1/128 of an inch.  The imperial fractions get hard to handle really fast.  By measuring a part in millimeters but setting the Sketchup drawing to use meters, I'm drawing everything 1000 times too large.  When I'm done, I simply scale it by a factor of .001, and reset the drawing preferences to millimeters.

Maybe there's a better way, but I haven't found it yet.

Ken Rickman

Danville & Western HO modeler and web historian

http://southern-railway.railfan.net/dw/
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Toniwryan Frequent poster 502 posts
Toniwryan

Full Size

  Drawing full size is the way to go and then scale to your preferred modeling scale.  Always save a "full size" version of your design and make a separate save of your scaled items.  Store them in different directories if you need help keeping them straight.

  That is pretty much the only way to get things into model scale in Sketchup.

Toni

 

Toni
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Benny MRH Author 7,125 posts
Benny

...

I do everything 1:1.  The tower file, for instance, was 1:1, from the rough cut.  This allows me to do all the work without thinking too hard, whereas a 6" board is 6," and when I get to the end, I just scale it down...

I have done a couple with scale dimensions, and while I can do it, it's easier the other way...

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Benny's Index or Somewhere Chasing Rabbits
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DKRickman Prolific poster 3,069 posts
DKRickman

It depends

If I'm trying to draw a prototype, I'll generally make a full scale drawing.  However, if I'm drawing a model, or parts of a model, I find it easier to draw it the size of the model.  That way, for example, .020" styrene is .020" thick instead of whatever that might be in the chosen scale.  A .5mm clearance is easy to measure, rather than measuring a much larger clearance and then converting it.

So it really depends on the purpose.  For many things, 1:1 is the way to go, but for others, 1:1 for the model makes more sense.  The 2-4-2 drawing I'm working on now is an example - I'm making it up as I go and using the dimensions of the materials I have on hand, including the mechanism.  If I drew the engine full size, all those dimensions would have to be scaled up.

Ken Rickman

Danville & Western HO modeler and web historian

http://southern-railway.railfan.net/dw/
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