Section View Tool Gone Haywire...

[Slagathor]

Out of the blue...the section view tool has offset itself so that the axis about which the 'section view front plane' rotates no longer coincidences with the coordinate system. So when I rotate the plane to section a part symmetric about my y axis based on the part origin...the section plane translates. This is a pain. See attached pics for reference. How do I fix this?

 

[Slagathor]

One more try on uploading the pics...

 

[Slagathor]

In the second pic, I rotated the section view 45 degrees. But the yellow vertical line is the axis of rotation for the 'front section' view plane. It is not on center with the part origin...so the plan rotates and translates...which is worthless. I know that I can translate is back...but zero should be zero. I have never had to correct it to zero before....

Any tips?

 

[CorBlimeyLimey]

Have you rebooted?

What SW version and SP?

Can you ZIP and post the assy and parts for testing?

 

[Mitsu50]

i just created a test part that look likes yours and it functions as it should. upload the part for testing. i'm not aware of any settings or control of this

 

[Slagathor]

OK..I figured out where the sketch element that causes this to happen occurs...but I am still baffled. This is absurd. Please see the attached files.

File 'Test 1':
*Simple sketch on Front plane
*All elements symmetric about the Y-Axis
*Fully defined/constrained
*The Front Section View is in the correct location


File 'Test 2':
*Same sketch in front plane
*Added a circle, to the right side and above the rectangular elements from 'Test 1'
*Fully defined/constrained
*The Front Section View now shifts to the right...and if it is trying to move to a balanced point on the sketch!

Ridiculous. I have never seen anything like this....

 

[Slagathor]

Here is the file 'Test 2'

 

[Slagathor]

This problem has something to do with auto sizing behavior of the section view tool. When you make a sketch that is not symmetric, it adjusts the section view version of the front plane. I swear it never did this before.

As it stands now...this makes the section view tool utterly useless...

 

[Slagathor]

One more thing.... SP 2010 SP 4.0 Forgot to disclose that previously...

 

[CorBlimeyLimey]

It took me a while to clue in to what you are seeing as the problem.

The plane you are seeing is being auto-sized to enclose all sketch and solid geometry elements. It is intended functionality.

http://help.solidworks.com/2011/Eng...cyhelp/sldworks/ref_geom/plane_autosizing.htm

 

[CorBlimeyLimey]

The yellow lines denote the "centre lines" of the cutting plane. They are not the axes of rotation.

Why does this make the section tool "utterly useless"?
Does it not cut the part where needed?

 

[Slagathor]

CBL,

I know that the yellow lines are the rotation points of the cutting planes for section view. That is the point! They MOVE as the part changes..and seem to do so in an arbitrary way. How can that make any sense to anyone?

So you make the part a little more 'right heavy'...and pivot axis of the view cutting plane moves to the right? That is just dumb.

It basically means that you can not use any of the section view tools at any angle, because you have no way of knowing the axis about where they are pivoting. The only way you can really know what you are looking at is to only use the original orthogonal cutting plan views.

There is even a feature where you can save a 'section view' as an 'annotation view'...for transfer over to a drawing....and yet you can not fully control the section view geometry. It is scary to think someone might actually use that tool at a slight angle for a mfg drawing without knowing that the pivot point has no relationship to the coordinate system. Such a feature, is downright negligent in my view.

OK...end of rant. I will now move forward. At least I know it is stupid by design..and not a bug or setting I missed.

This program truly is love-hate. Some things about it are just so excellent...and others are just plain failing grade stupid....

 

[Slagathor]

CBL,

Here are 3 files which illustrate the problem with this 'functionality'.

Test 3,4,5

Test 3 is symmetric. As such, SW keeps the front cutting plane pivot on the coordinate system Y-axis. I saved a 45 degree view from the front cutting plane.

Test 4. I added some mass to the right. Now the front cutting plane pivot has shifted to the right...and you have no idea how much it moved! With the cutting plane again selected..and rotated 45 degrees...you can see how the view is both rotated and translated. Every time you change the part...a view with the same settings...actually changes.

Test 5. I tried to re-establish the original view by eyeballing it. I shifted the 45 degree rotated cutting plan back about 12".

So the problem is SW moves the cutting plan pivots...and you have no idea where they moved to.... Even if you did..that means every time you part changes...you have to readjust your view.....

 

[CorBlimeyLimey]

Ah! Now I understand the problem.

Why not just create a plane at the required 'cutting' angle and use that in the section.

 

[Slagathor]

CBL,

Yeah...you can do that....but guess what. It auto-sizes those planes too...throwing of their pivot axis!

Try it...

So there is a way to control the section plane so it can safely be used for saving as an annotation view...but again...just as with the principle planes (front, right, top)...you CAN NOT ever use the angle feature in the section view dialogue box...and know what yo are getting.

You have to build the angle you want into the plane you select. If your part is not perfectly symmetric, and you change the angle...you don't actually know where you looking from. Doesn't that seem to defeat the purpose of having a quick adjust scroll bar the the angle.

This is typical of programmers...they think that adding some new feature makes something better.... It this case...it (sectioning planes that 'autosize') ruin the tool....

 

[SteveMartin]

I understand your frustration, but a question: why do you assume the section will rotate about origin? It actually seems to work the way I naturally assume for it to do so (rotating about the center of the cut body), though admittedly I hadn't thought too much about it until your post.

If you need control over the section, you can use a method that allows explicit control, such as creating a plane at your desired angle & location and sectioning via that (as CBL mentioned). You CAN fully control a section view for carry over to a drawing if that's your desire (though I'd have concerns with building a drawing in this way that have nothing to do with controlling how the model section is defined), it just takes a bit more work.

As far as I understand the section angle in the section property manager only ensures the section normal will be that angle off the reference plane normal. Anything more is expecting something the tool is not promising.

I truly fail to see how this behavior 'ruins' the tool. It's a matter of knowing which tool to use for which task. I've used section cuts at angles both via the dialog entry and via explicitly defined planes, they both have their places in my workflow. It's a trade-off: speed vs. control - a decision we have to make all the time (often subconsciously) in many forms to build models.

 

[Slagathor]

It ruins is because SW inserts an offset to the viewing plan pivot every time you change the model...

 

[CorBlimeyLimey]

I've always used the Section Views In Models (

http://help.solidworks.com/2011/Eng...sldworks/display/section_views_in_models.htm)

as a purely visual display; never for manufacturing needs.

When the precision for manufacturing is required, I use the intended drawing sections, or an extruded cut of the model in a config.

The Instant 3D Live Section Planes may be what you are looking for.

http://help.solidworks.com/2011/Eng.../sldworks/features/instant3d_live_section.htm