I’ve made my wheels 3D and was trying to make a curved from the wheels to the body. However, they are not making a face and is instead see-through. I’ve gone over all the line yet it still not making a face

The lines aren’ t coplanar.

what does that mean?

There is no mathematical plane possible that ’absorbes’ the two edges, there is one endpoint that ‘sticks out’

Technically speaking, there are no lines in SketchUp geometry, only ‘edges’

An edge has two endpoints (lines do not have endpoints) and if you have two edges, all four endpoints need to be in the same (mathematical) plane in order to create a face.

Try it with triangles

I cant. Do you know on the car the have the wheel arcs and that where the wheels go? From the wheel arcs I’m trying to curve from the arc to the body but it not making a face like it suppose to do. My dragster.skp (457.2 KB)

The shape you want to make is a complex curve and will not automatically form in SU. All things in SU are made up of edges and faces and the edges need to be coplanar for faces to form. This just means the edges need to line up on the same plane. The three points of a triangle will form a face, so complex curves are generally made of triangles with softened edges between them.

This gif shows the basic premis of stitching a complex curve surface. Note the use of the endpoint inference. I use the eraser while holding ctrl to smooth the edges.

This is only one of many ways to create shapes, but hopefully it will help you understand the underlying geometry of Sketchup.

It not working for some reason