Wierd triangles


Sometimes I’ll draw a rectangle and when I click the enclosed surface I will end up with two or more triangles from one corner to the diagonally opposite corner with no visible dividing line instead of the rectangle that I drew. Why does this happen?


It sounds like you have hidden geometry lying around that is intersecting with your model.
A screen shot and a model would help us to fully diagnose the problem.


Are you using layers?
Have you been using the Hide command?
Have you seen either of these warnings popup?


I don’t get any error messages, and I can erase the individual triangles, then when I redraw the rectangle they come back again. I have not use “hide”. and am not using layers. I look all around in all kinds of views and can’t see any hidden things.


I repeat, why make us guess?!


If the problem is hidden geometry and rect. drawn self intersecting it would seem the error would be some what random vs corner to corner. The corner to corner sounds like an auto fold issue probably caused be the user, but … model will tell maybe.
Do not use fractional units, do not use snap to and use at least three decimal point display resolution( This has no bearing on internal res but aids TSing.), and input the rect. corners in the meas. control box which will over ride any snapping you have unless it gets within the tolerance threshold and a vertices could be moving. With blank SU open do a select all and then delete just encase there is some extraneous geo in the template .
Make sure you always use the interference engine!


In my models, there are plenty of times that I have to use fractions otherwise things don’t look right. Te rectangles are not always made with the rectangle tool, but a lot of times I measure out an area with the tape measure and then connect the measured points. What is TSing? What is the interference engine?


I would include a screen shot, but I have already deleted it.


Inferencing is SketchUp’s internal guidance system that helps you model accurately.
See these learning resources …

Inference — SketchUp Help


Inferencing Locking


sorry for lack of clarity: Fractions are a display precision and does not relate to SU model precision. When trouble shooting ( TSing) it can mislead some times. I will often use the text tool to list the x,y,z values of vertices when trying to sort why face is not forming etc. For example Su 32 bit has a 7 digit because of use of float. Your use of fraction and having to use tape measure tool indicates some type issue. If you do not use the inference engine then some times just the simple action of clicking the mouse can cause enough movement to cause a model error. I had an issue with that when first starting. My guess is you are moving mouse when you click and causes auto folds. Make very large rect then use rect tool internal to that and make sure you get an on face interference and the stray lines will probably not be show up.
Just some thoughts.


What is Tsing? I don’t know what this is. he reason I use the tape tool is I am making model items to import into a game I have and most of the times the measurements have to be precise, such as the length of a support post to the underside of a ramp, etc.



When you trace around a rectangle, it’s easy to get out of plane. Sketchup tries to find inferences, places where you correspond to other features in a model. It sometimes “adjusts” the spot where you click so it lines up with other geometry somewhere else on the page. Even a misalignment of a few millionths of an inch can keep a rectangle from forming a plane. When this happens, a fold line may be created (more often, you can’t get a face to form). A fold line would be hidden geometry, and would show up as a dotted line when you click View/Hidden Geometry. Otherwise, it’s not clickable and only shows as a difference in shading.

To repeat what mac7595 just said, TSing is troubleshooting. New one on me as well.


Thanks for your help, some of it is still greek to me, but I think I get the gist of it.