Preventing holes from creating on a cylinder when adding to them


#1

So somewhat noob question but I am trying to make a childrens toy to print. I’ve got most of it however I am having troubles with this one piece. It consists of a cylinder with blade type things wrapping around it. I’ve tried creating the blades off the cylinder and adding them, and creating them directly on the cylinder and either way it creates holes around the cylinder. I’ve tried repairing the holes but can’t figure out how to. I’m open to any kind of fix, be it a new way to build it or fix after it’s built or something else. Anyways, I’ve attached a file of what I want the final outcome to be minus the holes, any help is appreciated, thanks! :slight_smile:

fixing holes that get created when adding parts to a curved cylinder.skp (245.0 KB)


#2

Scale!
Sketchup has a tiny faces problem. It can’t form faces when the edge segments are too small. They can exist but they are difficult to create. Things start to be a problem when the segments start getting below 1mm, or the equivalent fraction of an inch.

So, scale your model up by 10 or 100 as needed (or 12 and then an inch is a foot) to form the faces and scale down when complete.
The scale tool and the tape measure both make it simple to resize exactly. You can also make you piece a component and used a scaled up instance to edit, then delete the big one and the edits remain on the small one.


#3

Size is not the only problem with the model.
Turn on Hidden Geometry and then inspect the model in Top View > Parallel Projection > X-Ray Mode.
Notice the cylinder wall is distorted in the area of the missing faces.
Generally, it’s quicker and better to start over than try to fix such errors.



Tips:
• Model the cylindrical core and make it a Group.
• Model one of the blades and make it a Component.
Rotate / Copy / Radial Array to create the other three blades.
• If you make the blade component pass through the wall of the cylinder you can Edit Component > Select All > Intersect Faces > With Model and then erase the excess geometry.
• If the Group and Components are Solids, then the Outer Shell tool becomes an option.