Many times over my years of intermittent Sketchup use, I have wanted to be able to input a list of directions and distances and have SU simply follow that to create a line drawing.

Recently I realized that this isi the basic concept of one of the very first computer drawing programs, Turtle Graphics. Implementations of Turtle Graphics have been done in numerous languages, from SmallTalk to Python. There's even a downloadable Python Module.

Turtle Graphics also seems a natural for Sketchup, but in poring over Sketchucation, the Sketchup Form, the web, etc, I can't find anything.

The concept is simple, you provide a list of directions and distances and the system follows directions.

N 1"
W 1"
S 1"
E 1"

or

0, 1
90, 1
180, 1
270, 1

will draw a 1" or 1 unit square.

Previous uses that I would have like to use it in have been measuring a room interior that is more complicated that a simple rectangle and pacing off the layout of pathways in a large garden site.

If I were to try myself at getting a Ruby Script to input the data and draw the line, it could take me weeks to get up to speed on all the different Ruby functions I would need. I can read some Ruby, but generating it slower than one hour per line.

Has anyone done this already? Is there someone for whom Ruby is a native language who could just whip our a demonstration version (sans bell and whistles of different data input formats, etc.) that I might augment?

Thanks.

P.S. Nice to be back on Sketchucation. It's been a while.

Could someone please edit the top post in this thread and the v2.0.2 page in the Plugin Store to point to v3.0.0 in the Extensions warehouse?

I installed v2.0.2 thinking it was the latest and spent well over an hour working around a bug. Only after finishing my task and coming here to report the bug did I find that 3.0.0 exists. I installed it and the tool worked exactly as expected, no bug.

Thanks.

@lothian said:

Can't seem to change the number of segments. Stuck at 24.

I had trouble with this too. In v2.0.2, the version available here on SketchUcation, I had to change the number of segments with the Circle tool first.

Doing that, I easily made an arc of 26" with 13 segments. Each segment was exactly 2". Constructing an arc out of fixed 2" segments would have been a LOT of work.

(It was "easy" after I figured out an axis orientation of my curve that didn't produce buggy results. v3.0.0 from Extensions Warehouse didn't have that bugginess.)

Hi Pixero,

That tool appears to, as it says, draw a line from the camera to the "target", the center of the camera field.

My tool, when active, draws a line from the camera through the selected point in the frame. So from a single camera position, you can draw the rays that outline an object.

Would it be straightforward to modify your tool to do that?

Thanks,
August

@pbacot said:

I think the Position Camera tool does the same thing if you set it to "0" height and drag it along the line, or am I wrong?

I don't use the Position Camera tool much but I don't think it's applicable. I'm not getting your meaning, for what I am seeking, of "drag it along the line." What line? Do you mean drag the camera, at zero height, along the ground. Not quite. My task is to create a new line, a 3D line, not one on the ground. Let me explain a little more.

My "Line-of-Sight" tool was initially primarily for photo matching, but I can imagine uses for planning movie shots as well, to plan what obscures what in a shot.

In use, you activate the tool and then click on a point in your view. Your click creates a line, but at first you see nothing because you have created a line relative to the current camera position and you are looking exactly down the length of the line. It's like shooting a laser beam out of the camera at any of the points in the scene that you are looking at. Shoot a bunch of them, while you are at it.

When you move the camera viewpoint with Orbit, then you can see the lines you created as all going through the original camera position and fanning out in 3D from there. Any particular line can let you identify everything that is along that Line-of-Sight that were all aligned in the original view.

My original intent was to use it for photo matching of things that don't have straight lines and flat planes, like trees and boulders on a building site, or even power poles, which are hugely difficult to place using Match Photo. With my tool, to position a tree trunk or power pole from photos, I shoot a line on either side of it in one view, switch to a different view and do that again, and again in a third view. Then looking from the top, I have six lines that show me where the tree looks to be in the photos and I can place the trunk in between them where it will align in all of the photos.

A few years ago a made a Ruby extension that does this, but it doesn't work with newer versions of SU. Someplace, in some thread, I got the idea that such a tool now exists in SU. I would like to know if that's true and what the tool is, before I put in the work of updating my my extension to work in the new SU.

Is there a "Line-of-Sight" tool in SU?

Several years ago I made my first (and only) Plug-in / Extension where you can click the tool anywhere in the scene and it creates a line exactly lined up with your line of sight at that point. So at first the line is invisible because you're looking right down its length. When you change the viewpoint, then you can see the line.

I remember seeing a reference a few years ago to a new tool in SU that does that kind of thing, so I'm reluctant to update the older Extension to work in the new SU with the new Extension policies if an equivalent already exists. But I've never found it.

Does a Line-of-Sight tool exist?

Can anyone shine a light on my vague memories?

Thanks,
August

Hi folks,

I'm on a new computer and in my first visit to SketchUcation in a while, instead of screenshots in threads, I'm seeing error displays from photobucket.com that tell me to check my account.

So is it the new computer, does everyone need to sign up for photobucket now, is the site broken, or what?

Thanks,
August

Hi Dan,

Thanks for a pretty amazing exploration of the possibilities. It's both educational and entertaining (for those of us who like this kind of thing).

My apologies for dropping the ball on getting back to you. This is one of those projects that I just keep whittling away at because each step seems a little more complex than I had expected or was ready to deal with.

You provided quite an array of methods for finding the starting angle of a circle, and I'm sure some of those will be useful as I move forward.

As for my current stuck spot, I think what I'm really trying to figure out is how to specify the starting angle of a circle, a polygon, or a curve, relative to the previously placed circle or polygon, as I go around the knot placing circles.

When I use the usual tools to create a circle, the starting angle does not seem to be a parameter that is under my control. The image at the top of this thread shows where it defaults to, just using the standard circle-creating functions. I do not need to understand the logic behind those defaults, because that's not going to help me with my actual problem.

If I create a polygon, like a circle, I also do not know how to specify a starting angle.

I have to wonder, when you draw a circle or a polygon manually in SU, the point you drag out from the center becomes the starting angle. So what's going on under the hood? Is a default circle being generated and then rotated so that it's starting angle is where the cursor is?

Lacking that methodology, the only way I can see to create either a circle or a polygon where I get to specify the staring angle is to make a 360 degree curve. That feels unnecessarily limiting, but that's where I've gotten to.

My current thinking on my original problem is that I need to figure out how to place the new curve, based on the information I have from the previous circle/curve. I have the normal, which is derived from the current segment of the knot curve. I have the previous circle/curve. And I have the previous circle/curve's starting angle.

And, as you suggested, I have to deal with what the starting angle is relative to.

I have to figure out what starting angle I want to specify, based on the previous normal, the previous starting angle, and the current normal.

I think I'm going to have to nudge the starting angle of the next successive circle by just a little, so that as the sequence progresses around the knot, it does a slow rotation and comes back to the beginning. Does it want to go around only once? Or three times for the three lobes of this knot? Or what?

You gave me a great nudge that percolated for a while and now I think I know what I need to figure out for my next step. I hope that's not another year, but who knows?

Anyway, thanks for all the tips.
August

Thanks Dan,

That's a angle, not a point, but it may turn out to be useful. Thanks for the pointer (no pun intended). I'll bang around on it for a bit over the next couple of days.

As for terminology in the broad sense, I suppose that following the above lead I would call my "zero point" the "start_point" for the circle. But if there's nothing standardized, then
zero_point = circle[0][0]
still has an appeal.

August

P.S. If anyone has a better term for the starting point of the first edge than "zero point", I'll happily use it.