Hello, so i have the file attached and it is hollow, i want to 3D print it but it hollow, is an easy way to make this solid ?hollow.skp (180.1 KB)

The simplest option in this case is to erase the top surface and pushpull to size.

That works, thank you !

@DoubleHelix If you have the time, you might mark @Box’s answer as correct to solve this question.

That would be the Solution tab ?

Honestly, I don’t recall how to mark a solution! But I see that Box’s reply is now marked as a solution, so I suppose you figured it out.

Actually, although my answer does solve the problem in this specific instance, it’s not a very good answer as it doesn’t address the whole issue. My answer above only worked because the object had straight sides.

If on the other hand the sides were curved or angled you need to understand the underlying geometry. As SU is made up of flat faces you need to insert edges at the appropriate places to form those flat faces and to form a flat face the bounding edges need to be coplannar. Three edges always form a flat face, so triangles are often needed to construct a surface.

This is one of the fundamentals of sketchup that is the basis of the geometry.

As you see below I find the endpoints along the edges to stitch the face closed. Depending on the angle 3 or 4 edges are needed. Then once stitched, I use ctrl and eraser to soften the edges to form a smoothed single surface.

More complex faces might need a lofting plugin such as Curviloft or Extrusion tools.