Can't 3D print my model - non mainfold edges, intersecting faces, zero faces

Hi! I been modeling a car.
After spending lots of hours modeling, I applied the solidify modifier in order to 3D print it.
But…it won’t slice properly.
I check my mesh with the 3D print tools and…oooops!
Plenty of trouble.

If I click on make mainfold, I get rid of non mainfold edges and I get something printable, but I want to print a hollow body, and now the body is not hollow anymore, and some weird shapes can be seen.

Is there still hope to get this right, or maybe I should forget about it?

I tried to find help on stackexchange with no luck , also I asked to my blender course teacher, and he had no idea how to solve this.
Here is my file:

Hope I find some experts willing to help here :slightly_smiling_face:

Took a look at the file and there are indeed a lot of problems, it’s not something a program can fix automatically unfortunately.

The best way would be to start over and use the model you have as reference.

If you want to 3D print it, don’t hollow it out the solid areas of the model.

The slicer will automatically create the infill required, which you can adjust, generally keep it 10% or greater.
Slicers do require a ‘solid’ model with a proper inside and outside that don’t overlap (normals).

Generally if I want to print something, I design it with that in mind from scratch.

Thanks! What could have caused those problems? Pretty much all I did all the time was extrude vertices and create faces.
There is ot much point on starting again if I do the same mistakes.

Thanks for your interest. The idea was to make a surface model, than, use solidify, so I was able to print it, adding a 1.2 mm thickness to the whole body. Do you think it is still paossible to make this printable as a body shell?

I’m having a look at the model now. Generally, if you were to print for that, you can set wall thickness to 3 layers, which equals 1.2mm with a .4mm nozzle

Well if you want to take the time to fix the mesh.

The first thing you should do is remove doubles, select the whole mesh in edit mode and merge faces by distance.

Next you should remove all the modifiers except mirror, due to the complexity of the mesh, you will have to solidify the mesh manually but that can wait until the mesh is fixed. Go into edit mode and make sure nothing is selected then open the select bar > select by trait > non-manifold:

As you can see, everything that is non-manifold is now selected, you can ignore the selected edges that the mirror modifier connects to and the open pieces.

What you want to focus on are parts like these:

As you can see, pulling away the edge shows that it has a hole that needs to be fixed:

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Those are great instructions and explanations from GrimZA, here’s my take at the fixed mesh, pretty much doing those exact tasks.

I did remove the solidify modifier and close the model up manually after cleaning up the mesh.

GTOcorrections4.blend (2.6 MB)

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Thanks, that’s interesting work, but the idea was to print it as a body shell, that’s the reason of adding the solidify modifier.

Ahh, apologies I misunderstood.

Getting an even thickness is hard for complex shapes with the solidify modifier, the model pretty much exploded when I turned even thickness on. Otherwise a number of edges were too thin to print.

My idea was to do it like in this video. In the video he doesn’t check even thickness, and it slices good.