Sketching headache

If I add a new line and give it a length, the lengths should automatically be added to the end. Why would anyone want it to be added to the beginning of the line and move a bunch of stuff that is already finished. I am getting really frustrated when trying to sketch things that are dimension specific for manufacturing. I want to start from the origin and work around a typical view of a sketch without having to constantly lock everything I do so the logic doesn’t constantly move the rest of the sketch. Another problem with forcing me to lock things adds a lot of difficulty in later modifications because you can’t easily figure out what is locked and what is not. Is there some weird setting I am missing here?


The app should generally work as you described. Could you perhaps record a short video of when this happens and if it’s a more complex sketch, send over the exported .shapr file? There could be a problem specific to your sketch or workflow that we’d need to fix and a video and the exported design would help a lot. Thanks!

First off, I love Shapr3D and I think what you are doing has tremendous potential. I will do a screen record later. But you should know that this is a major problem for anyone using your program for CAD. Your XYZ origins should never move even .0000000001 without your consent. And that happens all the time in this program. Often without you noticing that a .007 change you made an hour ago moved all three. I have to constantly check it. If I had any suggestion as to how I would fix it. I would give the user the ability to establish the point of origin.

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Correction, In sketch mode, no change can move all three. But I hope you get my point.

Hi @CLEVE-ij I believe the issue you experience is mostly caused by the inability of constraining to the origin and the world axes. Will add support for that in the short term, in the meantime if you lock the first point you place in the origin, then no sketch constraint operations will move it.

I have tried that and still have it move. But here is a video of a simple sketch. It only seems to happen when you assign value that does not conform to the snapping functions. It stays snapped and moves everything else. And that is no fun at all.

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This is what happens when you lock the first point. But I know you will fix it. The sketch is five lines and a circle. But I think it will do the same with one or two.

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Consider the ramifications of this when you are zoomed in and do not notice until you have worked on a very detailed section for a decent amount of time. This is where an area selection tool would come in handy. I think I saw it once but I can’t find it. So I often have to rework everything.

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Long press with the pencil, then select the area…

Thanks for the video! I agree, sketches shouldn’t move in an unexpected way and we try hard to do that – but there could always be bugs or UX problems around it that we should absolutely fix.

Could you please check two more things for me?

  1. Could you record yourself creating this sketch from scratch? I know it’s a very simple one, but we actually take the order of creation into account to make sure such dimension edits work as intended, and I have a hard time reproducing the kind of behavior I see on your video.
  2. Do you have “auto constraining” turned on in “Constraint Settings”?


I don’t see anything locked here, only snapped/constrained. I found it a good practice with sketching in Shapr3D to select the first vertex of the first line you draw, and click on the lock to make sure it won’t move.

But I agree, we should allow snapping and constraining to the origin and axes, stay tuned, they are on our roadmap.


I updated my Shapr3D to the latest version last night. And I just recorded this new video. I had to simplify it quite a bit because your sight will only let me upload a 30 MB file. And a 20 second file is over that. I can’t find the setting on this ipad to down res a screen capture. So this is what you get.

The more complex the drawing is, the more I want to pull my hair out. Like I’ve said before, when working on a very detailed section and I make lines that are a few thousandths and it moves a section of the drawing that I can’t see when zoomed back out, it could go unnoticed until hours later and I have no idea what caused my dimensions to be out of print. It happens with and without auto constraints turned on. It occurs with different logic on the same kind of drawing from one sketch to the next.

Thanks, this video helps, we could reproduce the problem.

We could indeed be smarter here, we’ll look into it. We should also snap to world axis automatically, which would take care of some similar issues (but not the one specifically in this video), and that’s also on our backlog.

But we’ll never be able to be perfect at this on a theoretical level as the designs get more complex: it is not possible to guess perfectly what items you want to keep in place and what are the ones you want constraint solving to move. I know it can be a hassle, but as a general practice I’d suggest locking or dimensioning items incrementally as you create them to make sure they don’t move in an unintended way. Also, keeping auto-constraining on unless you have a strong reason to disable it also helps preventing such issues.

I really do appreciate you looking at this Peter. I’ll do what I can for feedback. It’s a complex program for sure, and I doubt it’s going to be fixed quickly.
Could you simply add a setting that adds new line material to the end or beginning of the line new line? That would give everyone a choice. One can easily guess what the default should be.

FYI, the status of auto constraint has nothing to do with this. But I’m sure you guys will see that pretty quick when you start messing around with it.
The problem always occurs when you create a line that is not the exact length you want. Then when you add a value it distorts your work. Since you can’t easily make lines that are .xx1 or .x12 with the pen, you often must input the line value on every single line new line you creat. Especially if you’re modeling a blueprint.

It’s as if the value being added is a negative number. Next time you see that happen, try to undo and enter a number that is a few thousandths it will react by subtracting from the beginning of the line and pulling everything towards the newest point in your sketch.

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Unfortunately, it’s not as simple as adding an option for which side of the line to move. The way it works is that every time a new constraint (logical constraint, eg. perpendicular or coincident or a dimension, eg. length or radius) is added to the sketch, the application “solves” the whole set of constraints. We try to apply some heuristics in this process, but ultimately the correct behavior is to treat everything that’s not locked as something that can potentially be moved to satisfy the entire set of constraints. Sometimes those heuristics are good enough to create results that one would expect, sometimes, as in your case, they’re not. But they’re always just heuristics and they won’t do a perfect job all the time no matter how much we tweak them. The only way to completely guarantee existing parts of the design don’t change is to lock them, either by locking the endpoints or by setting the dimensions of the items as soon as you create them.

One thing that we’ll add soon is visual feedback about what parts of the designs are locked / “fully constrained”. That’ll help you understand which items would potentially move and which wouldn’t at a glance.


Bravo!!! That will be a great addition!

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I understand the complexity of this problem. But if there is a line with an open end, it seems pretty logical that the length change should be on the open end, not the end that is connected to everything else.


Thanks Ski3r. That is exactly my point. The Logo Turtle never had any problem going the direction you told it to.

Agreed – this simple case is a bug that we need to fix. I just don’t want to raise false hopes that it’ll help in every situation, especially in case of very complex sketches.

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awesome, we are all here to make the software as good as possible!