Why are these points not coplanar?

[spawn]

Hi everybody.

I was doing something and there was four faces involved, but during the proccess of creating them I tried to be very careful about parallel lines and interfence points but it seems the last face is not coplanar. I don’t know why because the rest were made with success and that one wasn’t.

I have the following questions.

• How can make sure they’re not coplanar?, any tool or work flow can tell me that?
• Is someone able to show what’s wrong and how to fix it?

This is my .skp file:
notcoplanar.skp (87.8 KB)

Thanks in advance.

[DaveR]

The corresponding edges aren’t parallel so the corners can’t be coplanar. The guideline is parallel to the selected edge. Notice it isn’t parallel to the near edge.

[spawn]

I’ll try to redraw them again, but it was pretty weird, because I’m almost sure I did the same process for all of them.
I’ll keep you up to date.

[spawn]

The better choice to me looks to be copying the two faces that are correc and then flip them.
@DaveR, how did you draw that dotted line? I mean … did you do it with the proctator or the tape measure tool?

[DaveR]

I used the Tape Measure tool since I wanted to make a guideline parallel to the edge I showed selected.

[spawn]

Thank you so much.