Issue with scaling my Iso Drawing from SketchUp

scaling issue.layout (196.9 KB)


Newbie here, I am trying to scale my drawing that I imported from sketch up. I set the view to parallel projection and selected iso. However when I bring the model into layout I am having some issue. In the sketch up model tray in layout, I set the scale to 3/16. However when printing it or when comparing it to a line drawn in layout the model does not have a 3/16 scale.

Please help

and thank you.

I am really hoping to get some clarification. I am a pipefitter, and majority of the information we share is through isometrics. I am including my model as well. If some one could help me out it would be greatly appreciated.

Also if my question is not clear please let me know what additional information or clarification you need.

cheersoscar intermediate project Isometric2.skp (259.6 KB)

I changed the dimension units to feet (4 decimal places) and then drew a linear dimension along the 14.8125 foot edge, and LayOut says it’s 14.8125 feet long.

Even you yourself drew the same dimension (set to inches) and got 177.75 inches (which divided by 12 is 14.8125 feet.) So LayOut thinks it is exactly what SketchUp thinks it is.

I did however draw 2 vertical dims for the same vertical edge at the bottom of the schematic which LayOut says is 26.00 inches high. I then exploded one of them, and then drew a dim from the exploded dim’s arrow points and got a paperspace dimension that reads 0.3317".
This is a bit “off”. It should be 0.40625 inches (26/12 = 2.16667) * 0.1875 results in 0.40625 inches.


It could be because of the Parallel Projection perhaps?

How far off do you think the printout is ?

Layout has no special support for isometric drawings. It measures the scale on lines parallel to the image plane, as you want in a typical orthogonal drawing. In an isometric drawing the scale should apply to lines going diagonally away from the camera.

To get isometric drawings to work in LO you need to multiply the scale factor by “how much” these lines diverges from the image plane.

From some fiddling with a cube and diagonals representing the camera direction you can find the factor 0.8164965809277244. I use the Ruby API to measure precisely, but it is something you can write down and reuse. You can probably also do the trigonometrics and find an expression for this factor but I’ve been too lazy so far.

Once you have this factor you need to set up custom scales with it in LO. Enter a scale like normal, but multiply the denominator by 0.8164965809277244. For instance 1:100 would be 1:81,64965809277244. Remember to change the scale name, in this case to 1:100 (Isometric) or something similar. 1:81,64965809277244 isn’t very descriptive.

Also be sure the view is actually isometric. LayOut’s built in isometric view is NOT isometric. Neither is SketchUp’s if you set it while being in perspective projection. Make sure a cube is shown as a perfect hexagon, otherwise the scale will be off.



And if LO has a live Ruby API we could port Tape Measure and let you resize viewports like you resize components and models in SketchUp.2019-12-06_09h17_11

Unfortunately we have been waiting for that “IF” to become an “IS” for maybe 4 years now…

Trimble priorities are baffling…