Beginner trying not to pull his hair out



I’m trying to create walls for a 3D model of a house. I’ve managed to get parts of the walls in place, but when I try to erase what I think are extraneous lines, entire faces are removed instead of the tool joining the coplanar face with the adjacent one.

I know I can hide the lines using the erase tool, but is that the best practice? I’ve re-drawn this one section 3-4 times now and it just keeps doing the same thing. I haven’t had this issue with other sections of walls. In the image, the lines I’ve identified with red arrows are what I’m trying to get rid of

Thank you so much for your help!

  • Ed.


The top two are showing darker which suggests they are edges of a hole rather than lines in a face.
My guess would be that the walls either side of the door aren’t quite straight so they don’t meet properly at that point.
As for the lower ones they look like they should be ok but try turning on hidden geometry, View/Hidden geometry, and see if there hare hidden lines on the faces.

Attaching your model would make it easier to answer.


This may help as it will make you visually aware all lines are on axes as you build in your experience. If you choose the cross hair option it may seem annoying at first. But as SU inferencing becomes more apparent, you will find you are snapping to the correct point. Not hovering in and trying to generally locate where to land~place your point. Also the tool tips will will help inform you as to WHICH point you are about to select, especially in corners or where guide lines and other points are in close proximity.

Like you said: // I know I can hide the lines using the erase tool, but is that the best practice? // If you know it may not be right…why hide it??



Just guessing unless you upload your model, but I suspect that Box is right, and further that the problem resulted from the process you used to create the wall. Tell us if I am wrong: I think probably you drew the walls at floor level and then pushpulled them up to height. And because the left and right sections of this wall do not meet at the floor due to the doorway, you drew them separately. The problem is that when you do this you have to be absolutely scrupulous about lining the sections up or they will not join at the top. You must pay close attention to inference points or use guides to force alignment. Even the tiniest bit off, too small to see without zooming in tremendously, will keep the faces from merging.

Two items of warning about the “color by axis” style described in the article @mrwmrutski linked: Two wall sections can both be perfectly parallel but displaced by a slight amount; they will show the same on-axis color yet not join up! Also, this style works to within a tolerance. That is, it will show an edge as colored even if it is very slightly misaligned. It will help you find gross errors, but not the very subtle ones that can result from tiny drawing mistakes.


I think I fixed it. I deleted that entire wall and re-drew a rectangle on the floor and pulled it up, then created guide lines and punched out the holes for the windows and door. That seemed to do the trick. Thanks for the help; I’m sure I’ll have other questions in the near future.


Well, somehow I did it again. Including the model this time. Basically I want the three windows punched out. I tried to use guides and snap everything into place using the measuring tool, but still no go. Thanks.Dallas House3.skp (1.1 MB)


This time the problem appears to be that you did not pushpull the windows precisely to the back face of the wall - very close, but not exact enough for SketchUp to believe that they cut the back face. Each of the three windows has a slightly different symptom, so I suspect the issue is with your technique when pushpulling them. Here’s the right way:

  • Draw the window rectangle on the front of the wall
  • Select the rectangle and activate the pushpull tool
  • Start the pushpull back through the wall (pull well beyond it to be certain you are going the right way) and then move the cursor up to where the top edge of the back face shows. Hover/wiggle the cursor around there until you see an “on edge” inference. Click while that inference is showing to place the pushpull exactly on the back face. The window should then cut the wall.


Just to add, these two gentleman`s knowledge and info is much greater then mine. My point being, as you said a beginner. Was for you to better understand Inferencing and understanding that SU provides you with info and tools to help you connect the dots. It is not offered as a fix for any issue now or future. There are small but intricate things you (I still) dont realize that have a great bearing on / cause most of our issues. With a Warning applied, some may take it the wrong way. Not trying to provide wrong or ill advised info, just while you are frustrated and concentrating at the same time trying to get it right. Was and is when I am most prone to making mistakes. The cross hairs help me to better rely on and understand Inferencing and making me more aware of my placement. Noticing the different colors of the dots at endpoints and different words in the tool tips and not assuming… Good Luck with it…Peace…