Scaling down in Sketchup?

[Multiple identity account]

Hey guys,

I've been meaning to add as much (printable) detail as possible to my further models and for ease of design I thought of designing my models in real scale i.e. 1:1 before re-scale it down to 1:87 for printing. There are 2 issues (sorry if I sound stupid) but can you'll please help me with the following:-

1) I like to use 0.5mm handrails on my models (a little chunky but prominent). How do I calculate the size of the hole in 1:1 scale so that when I do scale it down to 1:87 it's 0.5mm...

2) How do I scale down the model to 1:87? Any direct way? I've been exporting my model to a new window with a 1:87 scale drawing and then slowly scaling it down.

Hope some one can help.

Cheers!
Jeff....

[Marbelup]

Well, a 1 mm hole on the model would be equivalent to 87 mm in 1:1 scale.

 

So, a 0.5 mm hole would be equivalent to ??? I think basic maths should give the required answer.

 

Regarding scaling down the finished model, would it not be easier to create the STL in 1:1 scale and then scale the STL, e.g. Using NetFabb Basic?

 

I haven't used SketchUp but my understanding, based on posts by other members of the group, is that it doesn't handle small dimensions well anyway, so it would probably be best to not try to do the scaling in SketchUp.

 

One thing to remember when working in 1:1 scale is to scale up design requirements such as minimum wall thickness, to ensure that the scaled down model will be printable.

[rovex]

Its been said before on here by other modellers that one way to deal with sketch ups shortcomings is to design the model in metres (so one millimetre on the model is one mere in the design). This gets round sketch ups problems with small radii.

 

You can change the "model info" by opening the window tab and going to "model info"

 

You then export the model in meters and when you upload it to shape ways tell it the model is in millimetres . It then does the scaling for you.

[rue_d_etropal]

One of the reasons I decided to buy software was so I could design the detail stuff.I don't think Sketchup had ability to export to stl format at the time.

One thing I have found, as have others, is that as soon as you design something in one scale, someone asks if it can be done in a different scale. I had not even thought of this at first, but with the software I use(Alibre), you just add a scale instruction at the end. It is also necessary to go through other instructions to make sure final wall thicknesses are not too small, or big.

Even if you don't buy it, try a trial version, making sure you have enough free time for the tutorial.

[Joseph_Pestell]

One of the reasons I decided to buy software was so I could design the detail stuff.I don't think Sketchup had ability to export to stl format at the time.

One thing I have found, as have others, is that as soon as you design something in one scale, someone asks if it can be done in a different scale. I had not even thought of this at first, but with the software I use(Alibre), you just add a scale instruction at the end. It is also necessary to go through other instructions to make sure final wall thicknesses are not too small, or big.

Even if you don't buy it, try a trial version, making sure you have enough free time for the tutorial.

 

That sounds really useful.

 

Presumably, after it has told you that some final thicknesses need modifying, you do that yourself. Or does it do it all? I am just thinking that the software might not quite understand our priorities as modellers and either add external thickness (ruining the scale dimensions of the model) or make internal dimensions too small for the intended mechanism.

[rue_d_etropal]

The software does not tell me what is too thin. There is something in the Shapeways software than can do that and I think there might be tools to fix any problems. I have learned by experience, and just work through the design in Alibre increasing or decreasing thicknesses. Main problem for me is my laptop running out of memory, so it sometimes takes longer than it should.

Most of my railway models started out in 1/35 scale, and I use a minimum thickness for walls of either 1mm or 0.9mm . When resizing to 1/76, I up the wall thicknesses to 2mm, which with a 46% scaling comes down to about 0.9mm. I have just started resizing these models don to HO scale, and strangely to go from 1/76 to 1/87, it is easier to apply another scale reduction of 87%. As the minimum printable thickness is about 0.8mm, this extra reduction comes down to 0.8mm so is still printable. If there are any handrails or small fixtures these need extra attention.

Another problem area is for wagon chassis where model gauge is not to scale, eg O16.5 and OO9, for 2ft gauge prototypes, so some wagons gets stretched slightly. O14 wagons presented a different problem, as there was not enough clearance so axle boxes were made as thin as possible.