# All I need is an irregular polygon 0~;

Hi All,
I’m a long term gardener moving over to garden design, looking for the best software to use, and I’ve just started the Sketchup Pro 30 day free trial.
I have to get a couple of “simple” plans done by early next week, and I’ve spent the last 2 hours trying to find how to do what I would have thought was the simplest thing - draw an irregular rectangle defined by its side lengths, and triangulation. I still haven’t found the answer!
Thank you!

Karsty.

First thing, are you sure you want sketchup, it is a 3d modeller and if you are only doing 2d plans there are more appropriate tools.

An image, some measurements, your model so far.
Otherwise we can only guess.

Here are two plugins designed for your needs.
You’ll need to register (free) at SketchUcation to be able to download the RBZ plugin files.

Hi Box

Yes, I want to build a 3D plan on top of a base plane (correct terminology?). The site is sloped, slightly, but that is not important at this stage. I just want to start with the real quadrilateral dimensions of the garden and build on it. Image of sketch attached.

Thank you Geo I’ll try it

I’m fairly good with computer techy stuff, and I’m sure I’m missing something, but how is it that such a basic thing is not permanently present in Sketchup?

I believe you need at least one angle to work from.

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If I can calculate that angle, is there a straightforward way to implement that shape?

Yes, you can start with a right angle of the correct lengths then use the rotate tool to change the angle then go from there.
You may need more than one angle.

Just as @Box noted, you need at least one diagonal dimension to solve the puzzle.

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Sorry, they’re not marked on the sketch, but I have both of the diagonals

Draw the two triangle and you’ve got it.

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Thanks guys,… I just solved it by using the arc and straight line tool, in the exact same way I used to in technical drawing at school!

That works, sort of.
The problem is Circles and Arcs in SketchUp are comprised of straight segments.
The result is varying amounts of error.

@slbaumgartner’s Circle Intersect plugin insures accurate results.

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Ok, thanks Geo. I think the method I used is going to be accurate enough for this project. (now I have to see if I can segregate the lawn I’ve drawn in with a number of arcs joined together. It just seems to want to stay as part of the default layer)

Be careful with your preconception of how Layers work in SketchUp.
They control visibility and nothing more.
More to the point, Layers do not separate/isolate SU’s sticky geometry.

Groups and Components keep things separate.
See these brief tutorials:

Components

Layers

Thank you Geo. I mean I can’t segregate it at all. I can highlight all of its perimeter lines using Ctrl and select, but it simply will not separate in order for me to save it as a component. I’ve put the question into another post, I thought
it would be good to separate it!

It’s mostly best practice to group items as you make them to make them easily “segregated” for editing.
Those groups, or collection of groups can be assigned to a layer so they can be visually toggled on and off. Those different layered states can also be captured in a scene too, so it is easy to toggle to the same (or different) view for showing permutations made of different layer visibility.
Thinking in 2D in a 3D world like Sketchup can have issues with having one flat plane on another flat plane and so getting the issue of “z fighting” where each item occupies the same 3D space and the graphics system cannot determine which to display and so you get that interference. (see moving it around in gif - the second one i have a few millimeters above the ground plane to avoid the issue)
In 3D per your garden, it may be better to have that shape be part of the bigger terrain as you may need to lower it down it into the larger field for a pond? Raising it above it could remain in a group as it doesn’t have to show as recessed, but could also be push pulled up.

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Thanks Whiterabbitdesigncompany.
I made this post for it, I thought it would be better to do so as it is a different question
https://forums.sketchup.com/t/how-can-i-segregate-a-shape-composed-of-several-arcs-and-a-straight-line/99648/3

Karst.

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are you talking about the wordpress plugins.?

Imagine building the polygon by joining pieces of wood with hinges. Because the structure is in general not rigid, the answer to your question is indeterminate except if:

(a) One side is longer than the sum of all the other sides - in which case no polygon exists

(b) One side is equal to the sum of all the other sides, in which case the polygon is degenerate of area 0
© Your polygon is a triangle - apply Heron’s Formula Shareit Vidmate APK

Here is a proof that the polygon has maximum area if all vertices lie on a circle. It also proves that for the maximum area, the order of the sides does not matter.

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