I'm having trouble with SketchUp accurately sizing my pieces

I’m trying to accurately set up my cut pieces for wood panel, but noticed that the math doesn’t add up on my model. i have a piece that’s 34" wide and i have planks coming in 1.5 inches from the sides so the middle should be 31 inches. However, sketchup is showing 31 and 1/8". What can i do here?

just a fyi - i double checked and the 1 and 1/2" planks are flush with the edge of 34"


Hmmm, i set my precision to 1/8"

Attach your model.

Ok, i put it down to 1/16 and i see, it was rounding like you said! I had no idea… now my model is all messed up !

Just to be clear, it hasn’t messed your model up, it is showing you more accurately what you modeled.


there are two ways of drawing in SU :
either you do it by hand, and trust the value it gives you (and you end up with rounding errors by accident)
or you type.

The only way to be sure your values are good is to type them. even if it’s simple, like 3", depending on your parameters you might end up with 3,0000001"
if you want 3", type 3".

Sometimes I’ll draw something freehand to get good proportions, then mesure (and get mostly weird stuff), then redraw with proper values on the side. might not look radically different, BUT at least I know it’s solid values :wink:

but hey, we’ve all been there. the reason some of us have these “good practices” to give is often because we’ve been there. mistakes can be lessons :slight_smile:

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