How to close holes in a body/mesh?

[infoSDYW5]

I have a mesh file (STL) of a bike frame. 

I want to prepare this file, so that it can be 3D printed.

In order to do this, I wan to "close" all the holes that are in the model (e.g. the tube holes and the screw holes).

Here is what I tried:

1. Import STL mesh

2. Repair mesh (wrap)

2.1. (optional) - Remesh

3. Convert mesh to Solid

4. Identify a "hole"

5. Create a plane through 3 points (along the "hole" in the solid)

6. Create a sketch on the plane made in step 5, project 3 points from the "hole" in the solid, create a 3 point circle using the projected points, add an offset if needed

7. Extrude the circle sketch created in step 6 towards the solid body, ensuring that "join" is an option (not "new body/component)

Despite doing all this, my solid body still is not recognized as fylly "patched/closed". 

This results in an error in 3D slicers, such as OrcaSlicer, which processes the solid as having empty space between the tubes.

I am looking for any guidance, tips, tricks or advice in general, either to verify and identify where the solid is not "watertight", or on how to fix the issue and successfully patch/close all the "holes".

Attached is the STL file of the bike frame, if you want to give it a shot.

[jeff_strater]

You might want to consider fixing the holes in the mesh, not in the solid environment.  I couldn't find any holes in a very quick glance at the mesh, but if there are some, you can first do a "direct edit" on the mesh:

Then, you will be able access "erase and fill":

That can help repair holes in a mesh.

If all you want to do is 3D print, there is then no reason to convert to a solid.  It is only if you want to do "solid stuff" to the model that you should convert to solid.  Even then, a faceted mesh->solid conversion will be less than ideal.  There won't be any cylinders in your solid, and the solid will be very heavy and failure prone, depending on the operations you want to perform on it.

[infoSDYW5]

Thank you for the reply, maybe I was not clear enough. When i reference "holes", i mean the ones as shows in the image attached. Still struggling to find a way to close these.

[jeff_strater · Accepted solution]

This is the sort of thing I was talking about:

Completely up to you whether to do it in mesh or solid, though

[infoSDYW5]

Thank you sir, this is what I was looking for! The video demonstration was extremely helpful. Have a nice day!