Messed up model, quads?

I think I messed up my model. I read that you have to work with quads but somewhere along the way I messed up and now I have a triangle. Is there anyway to make this triangle a quad or have I messed up my model?

The shading is messed up in the quad right next to the triangle. Is that because of the triangle?

While Lemon's answer about the shading sounds correct, and use of triangles is a subject that can be debated for hours, I thought I would add some suggestions for adjusting the topology you have.

I see two ways to quickly get rid of the triangle you have highlighted.

1. Add an edge loop ⎈ CtrlR that will terminate at the triangle. This adds a fourth vertex to the triangle turning it into a quad.

1. Split the mesh that connects the triangles on each side and add in an extra face loop which adds another triangle that you can merge into a quad. With the vertices selected press V to rip the selected vertices. You can also use ⎇ AltV to rip and fill in one step.

• I agree and upvote. But as we don't know where the loops are going on the back part (approach #1), this can lead to unwanted results. Spiral loops for instance... but that can also correct a potential spiral... Apr 30, 2017 at 11:21
• Thank you so much! This fixed my problem with the triangle. The extra loop was no issue on the back part.
– Alex
May 1, 2017 at 7:23

I'm quite sure this is not because of the triangle, but much more because there is an additional vertex or edge hidden behind.

Something like this:

Keep in mind that triangles are not absolutely forbidden. And that a triangle becomes quads when a subdivision surface is used.

I think the good rule about them is: use them only if necessary and only if you know/master the consequences.

• The tris aren't and can't be forbidden, they indeed will be subdivided into quads when subsurfed and in many cases that'll be enough; the problem can be in the edge flow of that subdivision. It might not fit the curvature of the rest of the mesh and then you will have bad shading which will be caused (in that possible case) with tri. Apr 30, 2017 at 13:24
• Thank you for your reply! There was indeed some messed up vertices that I had missed, and the shading problem is now gone.
– Alex
May 1, 2017 at 7:26