Section cuts of revolved assemblies cannot exclude parts

[ejuarist]

I am generally having problems with section cuts of a simple assembly of revolved parts with holes (flanges, covers and screws).

When I use the "aligned section view", using a simple sketch of 2 or 3 lines, the resulting view
has parasite lines and does not show the screw threads, even when I insert them using "insert model items".

My original goal was to have a 3-segment section line with a concentric arc in it, because I want to show items which are located at different angles
and things get even worse. No thread lines and it becomes impossible to exclude certain items using the "section scope" feature - they are relocated or simply disappear.

This is very repeatable and looks very much like a bug in the software. Any ideas?

 

[CorBlimeyLimey]

It's hard to say without seeing and testing the parts. If you suspect it to be a bug you submit it to your VAR. They will soon confirm it.


SW07-SP3

 

[handleman]

Sorry, I'm not quite clear on what you're trying to do. Are you trying to force a section view by putting a cut feature in an assembly file, or are you trying to create a section view in a drawing? I can't even get SolidWorks to accept a section line sketch containing an arc, much less generate it correctly.

 

[ejuarist]

Ok, I'll give a little more detail.

I want to make a section view in a drawing from a complete 3D part.

I have a rather simple assembly of about 6 parts, all axisymmetrically arranged and parallel but in different quantities or angular locations (2 M12 screws at Rad 50, 12 and 6 o'clock, 16 springs at rad 40, 4 x M5 screws at Rad 30 2/5/7/10 o'clock). I want to show all of them in one section view.
So ideally I should do a section view with a section line made up of 3 segments: one from 12 o'clock to center, one from center to let's say 4 o'clock, one concentric curve from 4 to 5 and one from 5 to outside (still intersecting the center).

This works if you use a suitable sketch and does not look too bad (note that it only works with section view - NOT with aligned section view).
Problems arise however when you start excluding the fasteners - then they disappear or are relocated. And the threads are only shown for half the section, if at all.

Note that all this works OK in a section view made up with 2 lines only, intersecting at the centre.

I have also tried replacing the concentric arc with a straight line, but then I get parasite lines and strange cutoffs.

I am kind of surprised that I could not find any references to such problems on the net. This stuff looks kind of basic to me!

Hope this clarifies my predicament!

Enrique

 

[ctopher]

You can't use radii in section lines.
Also, from SW Help:

To create an aligned section view with more than two lines, you must select the sketched lines before clicking Aligned Section View . The lines must be connected at an angle and cannot form multiple contours.

Chris
SolidWorks 07 3.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 03-26-07)

 

[CorBlimeyLimey]

Sorry Chris ...

You create a Section View in a drawing by cutting the parent view with a section line. The section view can be a straight cut section or an offset section defined by a stepped section line. The section line can also include concentric arcs.

http://img45.imageshack.us/img45/986/sectionwithconcirclerv3.jpg

SW07-SP3

 

[handleman]

The difference is Section Views vs. Aligned Section Views. Enrique made this distiction in the middle of his last post. Aligned section views can't have radii, but regular section views can.

 

[ejuarist]

Thanks for the image CorBlimeyLimey, that's pretty much the kind of thing I am trying to do!

Only I want to show this in an assembly with several parts and washers. Apparently ISO demands that fasteners not be sectioned (hence the "exclude fasteners" function in SW). This looks however like a disaster when complicated section lines are used...