Draw a triangulation?

Is it possible to draw something by showing the triangulation measurements from another point?

For example, I’ve measured a garden and triangulated the position of trees and buildings from each other. I’d like to now quickly draw these elements onto a plan in Sketch up. So, say I represent 3 trees using circles, can I move a circle around while seeing its distance in relation to the other two circles? Hope that makes sense!

Use crossing circles or arcs to identify the locations. TIG’s True Tangents plugin from Sketchucation might be helpful, too.

Here for example I’m assuming a tree located 24 feet from the lower corner and 27 feet from the upper right one. The tree must be where the two circles intersect.

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Ah, great idea thank you Dave. I was hoping there might be a way I could see the distances and move the circle around until in the right position, but this seems like a sensible alternative that might actually be faster than moving a circle around to guess!

There might be a way to do what you are thinking but I’m not sure where you would be moving the circle to.

It also might make sense to just use guidelines.

If your borders are on axis and you know the location relative to a corner or some other identifiable point you could place the circle for your tree on that point and then move it using Relative Coordinates. Start moving the tree and type ,x,y,z> and hit Enter. If you don’t want to change the z-value, just type <x,y,> and hit Enter. You need the comma after the y-value but you don’t need to type the z-value.

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You might also consider trilateration if you have measured distances between multiple objects.


Oh, yes that does sound like it does what I’m thinking of - I have measured all of the trees of site using trilateration, so to be able to then draw two lines to mark the next tree would speed things up a lot.

Relative coordinates sound like it might help too - I’ll try this morning. Thank you!

Trilateration is the answer, it’s clunky because you can’t see exactly where you are specifying the two starting points from, and the resulting position is often out by 5 - 20cm but it’s the fastest way to work this out.

I have to then adjust the location manually and keep checking the triangulation points using the measuring tool, but I’m gradually working through it. It feels like an oversight for SketchUp not to have this function built in, it’s one of the fundamental ways of surveying land accurately and then translating it back into a working scale layout. Hopefully it will be one day.

It’s not clear to me why you “can’t see where you are specifying the two the start points from”. Please explain more and/or provide an example so I can help sort it out.

Do you mean that there is no live feedback of where the cursor is positioned, so you have to eyeball/guess where to click? That is typical of almost all tools in SketchUp: the workflow is to use inferences from pre-existing points and directions, starting with the origin and axes in a blank model, not to try to click absolute point coordinates in empty space. You can, for example, create guides at specified offsets from the axes or existing edges (tape measure tool) or at specified angles to the axes or existing edges (protractor tool) to get intersections at desired absolute points. Then use these intersections when you click to place baseline points. There should be no inaccuracy in these points if you type in the required measurements when creating the guides.

You can then draw an edge between those two points to serve as a baseline for the trilateration. For additional triangles you can either use the same baseline again, use a side of the first triangle as a baseline, or create a second baseline to start an independent triangle, depending on how you took your measurements.

I hope you don’t mean the guide points created by my trilateration tool, because the calculation of their positions is as accurate as computer math allows, probably microns on a typical size model. But the calculations are GIGO; if you don’t establish an accurate baseline, that will propagate through the trilateration.

Agreed, that’s why I created the extension. I suppose it was overlooked because SketchUp wasn’t originally conceived as a surveying tool and Trimble has alternatives for that in other parts of their suite.

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Agreed. I may have a way to get this tackled with SketchUp’s native tools. All depends on what exactly you have in mind.

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Sorry @slbaumgartner I didn’t realise you’d made it, I would have used less blunt terminology as it has really helped me!

What I’m struggling with is that I first click a surface to set the plane, then when I click to set the centre of the first circle, it isn’t clear to me if the centre starts from where I click or where the sketchup marker moves to. You know the red or blue squares and green circles? These are often away from where my cursor is.

E.g. I am largely working off of the corners of the last triangulation points, but the sketch up marker is often further down the edge, rather than on the corner. Should I ignore these?

Thanks again for making it, it is helping me create a plan that would be much harder otherwise.

Screenshots are tricky as the cursor vanishes when I take it, but in the below example, I have the cursor hovering over the guide point in the centre of the circle, but the blue square is off to the bottom left of that slightly. Is the trilateration started from the blue square or where i have the cursor?

Screenshot 2021-10-13 at 09.21.44

I see. I think the issue is misunderstanding of where the “hot spot” is on the trilateration tool’s cursor. It is at the lower left corner of the cursor, where there is an arrow, not at the center where the two lines cross. I should revise the cursor image to make that arrow more conspicuous - as is it is tiny and easy to miss. I’m not home now, but when I get back I’ll create a revision on which the hot spot is more obvious. In the mean time, you can go by the cursor corner and watch for an inference snap on the guide point rather than on the face.

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A ha! Thank you so much, that is brilliant thank you :slight_smile: Yes, that makes sense now.