Surface faces to solid

[oldrebelworkshop]

Newbie to 3D and Fusion 360.  I have found a website that has a ton of 3D images, cars, trucks, etc, downloadable for free.  The only problem, they were not designed for 3D printing.   Most, if not all, contain only surface faces.  I've been trying to find a way to convert these for printing so I can use them in my model train layout.  The files are in .lwo or .max.  I have found online programs that will convert to .obj, .stl, .step but so far, I've not found anything that will convert those to solids for printing.  I have attached a sample .obj file.  Does anyone know of a program that will do the conversion that I need?   I've downloaded Meshmixer and Blender, as well as  Fusion 360, but am just not familiar enough with them to find the solution.  Any, and all, suggestions appreciated.  I am strictly a novice, so simple is my friend.  Thanks

[davebYYPCU]

Fusion 360, could get you going, you will need to find the models in step format, not obj, or stl, for a better workflow

load, open , import,  Step file, select all and Patch > Stitch them together, then Create > Thicken, your design intent from here is an open book.

Export as Stl.

Might help....

[thoreaubakker]

hey @oldrebelworkshop

I'm a rookie too, but I'll pass on what I know.

It's been my experience that to create a solid from faces is quite difficult, especially when there are large'ish holes (like the underside of your car and windows).
There may be a way to just thicken the mesh to create a wall, but I'm not sure how to do it.

I may be wrong here, but I think this may be one of those cases were there aren't a lot of quick options for you.

You mentioned you're new to 3D. Do you have any experience modeling? It might be worth getting few modeling basics under your belt before trying your current task. I'm struggling a similar situation myself.

t.

[TrippyLighting]

A quad mesh in .obj format is fine as it can be converted into a T-Spline. I do this quite often as I don't model T-Spines in Fusion 360 but use Blender.

However, this mesh unfortunately is triangulated garbage. It is low poly so can be covered directly into a BRep, but obviously it's not going to look smooth.

[oldrebelworkshop]

Thanks all for your time and replies.  Unfortunately, I just had a family emergency and have to put this project on hold so will have to wait to try your suggestions.  I appreciate your input.