Body Disappears in design window

[gtprototype]

Very strange behavior, I haven' a clue how to replicate it to do a screencast.

While creating a part in the design window all of a sudden the model will disappear and I haven't found anything that I could do made it visible again. 

The first time it happened I saved the file with a new name (to preserve my previous work) and re-opened the newly created file which resolved the issue.

The second time it happened I noticed the body was also missing from file icon in the design explorer.  I saved the file without renaming and the file icon updated to include the body in the design explorer.  When I re-opened the file everything was back to normal.

Perhaps not related however, I've noticed some wonkyness with sketches too; things like not being able to select geometry or constraints.  Another thing that I encountered was not being able to offset a spline; instead of it offsetting to one side I get a complete line encompassing the entire spine from both sides with arcs at the ends.  Additionally, I'm having difficulty shelling to the outside an object created from splines.

I'll prepare a file to share and post it.

[gtprototype]

File Attached

[HughesTooling]

Can't see anything wrong in the design you attached. Well apart from you probably need to learn to take advantage of the timeline and edit or delete features from the timeline rather than adding features at the end. For example the delete faces in your timeline, you should have just edited the features that created the extrusions not use delete.

Probably be a good idea to stick to one problem per post. The problem selecting constraints is known, not sure if there's a fix yet but just toggling constraint visibility will make them selectable again.

If you have a design you can share with the spline offset problem, create another thread and share the design.

Mark

[HughesTooling]

Looking at your first sketch, I'd recommend not mirroring in a sketch. The symmetry constraint uses a lot of resources and will slow the sketch solver, not surprised you're having problems with sketches if they are full of symmetry constraints, try keeping sketches as simple as possible. If you need symmetry, sketch half, extrude then mirror then extruded body.

[gtprototype]

@HughesTooling 

Thanks for having a look.  The deleted features at the end of the time line were intentional for the subsequent use in a distributed design of multiple unlinked instances down the road.

I presented all of the problems in one post because they all were experienced in the same design, even the spline offset at one stage.  I created the post for the disappearing body because the was no work around being that it completely stopped my workflow.

Thank you for the suggestion to mirror the extruded body instead of the  sketch; I will try to adapt my thinking to that strategy to overcome the sketch limitations.