I’m working with a fairly simple model that “seems” to have exact dimensions. When I measure with the tape measure tool it’s showing exact dimensions on both of my axis sides. But when I try to create a rectangle around the same dimensions, the measurements area is showing ~approximate measurements.
This usually tells me something is off in the model. Why would SU tell me it’s approximate and exact at the same time?
Attach the model.
You should increase your dimension precision and turn off Length Snapping in the Window>Model Info>Units dialog.
Are there any other suggestions regarding this problem? My length snapping is off and precision is set to 6 decimal places (far too much for architectural purposes) - still getting approximate measurements.
I would like to bisect an angle. However something in regards to the approximate angle means that the result is two different bisected construction lines.
ApproximateMeasure2.skp (3.0 MB)
Are you typing dimensions as you are creating geometry or just dragging things out and trying to eyeball it?
By what method are you bisecting the angle? I get the same numbers on both sides of the bisector and their sum equals the total angle.
Bisector.skp (3.1 MB)
I get the same result as Dave.
Don’t forget that you can show up to 3 decimal places for angular measurements in Model Info → Units.
Thank you both.
So two things I would like to resolve:-
Firstly - the overall angle being an approximate.
Secondly - bisecting that angle.
First - I redrew the angle manually and it draws accurately and there is a visual difference between the approximate angle and redrawn angle. Do I perhaps need to redraw the entire form in order to remove the approximate measurement?
Second - Assuming problem 1 is solved then I expect that problem 2 will follow. However I suspect there may be a method that others utilised that I am unaware of. I have been manually calculating the bisecting angle and drawing it. Is there an intuitive SU method?
First, what information are you using to draw that angle? Do you have the actual angle or is it the result of other numbers. If the angle is the result of Lengths and bearings of the edges, consider that the the precision of those numbers will affect the precision of the angle you get.
Second, I didn’t calculate anything. I used the Arc tool (not the 2-Point Arc tool) to draw an arc between the two sides and then drew the bisector between the apex of the angle and the central vertex on the arc. Here a 4-sided arc makes it easy to see the correct vertex.
On the subject of approximate dimensions, you need to consider the precision of the data set you are starting with. There’s no reason to expect the dimensions you get in SketchUp would be any more precise than what you start with. For example, I’ve modeled a lot based on the dimensions from the official survey. The edges shown in blue are drawn to the lengths and the angles given on the right. The arc at the top is drawn to the given radius.
With that said, the difference in the length of the edge at the bottom right is less than 5/64 in. and the length of the arc varies by less than 7/32 in. I expect the precision of the surveying equipment has a larger tolerance than that.
Another way of drawing the bisector is to rotate a copy of one side and superpose the copy on the other side and then add /2 in the Measurement Window or VCB for old timers. This creates an intermediate copy at mid point between the two sides (the bisector).
This trick can be used to divide an angle in as many parts as you want.
Thank you. A use of existing native tools to achieve the purpose. I thought perhaps there was a tool I was unaware of. Apologies and thanks.
Now that’s handy to memorise. Thank you so much.
