Fusion360 Can't select everything in my sketch and my extrusion has extra features (possibly related?)

[ebendler]

I have 2 issues. I don't think they're related but maybe they are. 

1. I've asked my students to make a cube. We first drew a square and then extruded it. In this student's sketch, there's an extra blue box that I cannot select or delete. I can't figure out what it is or if it's affecting the extrusion at all. Sketch view - I can't select the smaller blue rectangle.That sketch in solid view - it's clearly part of the sketch here but I don't know if it's affecting anything.
2. My second problem in this file is the extrusion on the face with "4". The center of the "4" is cut out. When I zoom in on the extrusion, there's a strange thing happening with the inner, slanted edge of the "4". It's no longer a straight line and is instead curved and appears to be overlapping. I think that's what's creating a problem? I don't understand why I can see through the cube, either, since the extrusion of the cube is solid. Zoom of the "4". Notice that the inner slanted portion is not a straight line.

Thanks in advance for any insights!

[jeff_strater]

can you share the model here?  The second issue looks to me like it is a graphics issue.  We are looking into these, so having another test case would be helpful.  The first issue, I think, is a different one, but having the model will help us look into that, as well.  Thanks.

[edit] forgot to mention, a workaround for the graphics issue can be to change the display detail control on the body:

choose "Fixed", and try any of the 3 options there.

[ebendler]

Changing the settings in the display detail control didn't solve the problem. I can still see through the cube. 

And sorry! I'm new to all of this. When you say share the model, what precisely do you mean? I want to make sure I give you what's needed. 

[jeff_strater]

sorry - the best way is to go to the File menu, do Export, choose "Fusion Archive (F3D)" as the type.  This will export the design as an F3D to your local disk, and then just attach that F3D to your next post here.  Thanks!

[ebendler]

Here you go! Thank you for your help.

[jeff_strater · Accepted solution]

sorry for the delay.

For some reason, this version of your design does not show that small rectangle in Sketch1.  I've seen things like this in the past, so I know the problem exists, but I don't see it in the model you shared.

The problem with the extruded "4", though, does exist.  I think I see what is going on.  I think it has to do with the font used for that 4.  I don't have that font on my computer, so when I edit the sketch, I think it is defaulting to some system font.  But, if you look closely at the faces of that 4, you can see the badness:

There is a lot of self-intersection going on there.  I'm a little surprised it succeeded at all, but the result is a bad body, and that is why the faceting is going wonky on it.

The one thing I would recommend is:  edit that sketch, select the text, right click, and choose "explode".  That will convert the text to curves.  Then you can try using Trim to get rid of the self-intersections, and you should get better results.  If you want to try the explode, then re-share the design, we can take a look at it.

[ebendler]

Thank you for finding the font issue! I went in and edited the font my student used and the "4" extrusion is perfect now. I don't think there's any particular reason that he chose that font so in my mind, that's the better solution than converting it all to curves. We're all new users and the more complexity I add, the more likely it is for something to go drastically wrong. 🙂 Thanks so much for your help!