Fix chimney hole

[TaiSakuma]

ChimHole_height was a bit too short for the solid subtractions to work properly. I made it long enough for the subtractions to succeed.

I think that the chimney hole was rotated to a wrong angle. I changed the angle such that the orientation of the hole makes more sense on the magnet.

[cmsbuild]

A new Pull Request was created by @TaiSakuma (Tai Sakuma) for CMSSW_5_3_X.

Fix chimney hole

It involves the following packages:

Geometry/CMSCommonData

@Dr15Jones, @ianna, @ktf can you please review it and eventually sign? Thanks.
@ghellwig this is something you requested to watch as well.
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@smuzaffar you are the release manager for this.

[ianna]

This should be compared to an engineering drawing before it goes to a release. As far as I remember, there was a fix for that already.

[TaiSakuma]

This is what I get without f914415

This is with f914415

[ianna]

I think, none of them is correct. Please, see the drawing attached.

[ianna]

There was a fix from February 2012 to fix not only the rotation, but also a union shape subtracted from the volume which was not correct.

[ianna]

[ianna]

@TaiSakuma please, test 57cd68d

[TaiSakuma]

This is with 1e4c6fe and 57cd68d

The image looks the same as the screenshot from @ianna's but looks different from Fig 9.1.

Without 1e4c6fe, the height of CHIMNEY_HOLE_P and CHIMNEY_HOLE_N will be too short for the solid subtraction. It will be exactly the same as the thickness of the wall of the MGNT. And since MGNT has a cylindrical shape and its wall is curved, the solid to subtract needs to be somewhat taller than the thickness of the wall.

[ianna]

Thanks, Tai!

Yana

On Sep 17, 2013, at 3:09 PM, Tai Sakuma wrote:

This is with 1e4c6fe and 57cd68d

The image looks the same @ianna's post.

Without 1e4c6fe, the height of CHIMNEY_HOLE_P and CHIMNEY_HOLE_N will be too short for the solid subtraction. It will be exactly the same as the thickness of the wall of the MGNT. And since MGNT has a cylindrical shape and its wall is curved, the solid to subtract needs to be somewhat taller than the thickness of the wall.

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Reply to this email directly or view it on GitHub.

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Ianna Osborne
CERN, 6 2-013
CH-1211, Geneve 23, Suisse
+41 22 76 70968
ianna.osborne@cern.ch

[ianna]

hmm... the shape is correct, but it seems too big in comparison with the other one.

On Sep 17, 2013, at 3:09 PM, Tai Sakuma wrote:

This is with 1e4c6fe and 57cd68d

The image looks the same @ianna's post.

Without 1e4c6fe, the height of CHIMNEY_HOLE_P and CHIMNEY_HOLE_N will be too short for the solid subtraction. It will be exactly the same as the thickness of the wall of the MGNT. And since MGNT has a cylindrical shape and its wall is curved, the solid to subtract needs to be somewhat taller than the thickness of the wall.

—
Reply to this email directly or view it on GitHub.

---

Ianna Osborne
CERN, 6 2-013
CH-1211, Geneve 23, Suisse
+41 22 76 70968
ianna.osborne@cern.ch

[TaiSakuma]

I agree. At least the chimney itself is much smaller from this photo
http://web.ethlife.ethz.ch/images/Cern-CMS-l.jpg

Also, the magnet seems to have another hole
http://cds.cern.ch/record/43056/files/magnet-2002-022_01.jpg?subformat=icon-1440

from a different angle with all cables.
https://cds.cern.ch/record/1274457/files/20071127_005.JPG?subformat=icon-1440
The chimney is near the top. This is much smaller. And then there is the bigger hole

[ianna]

-1
so, the inner opening in the release seems to have a correct width. I think, the other thing is a suspension point.

[TaiSakuma]

I see.

I tried drawing MGNT_1 and CHIMNEY_HOLE_N.

dz of CHIMNEY_HOLE_N is the original value of [ChimHole_height], i.e. ([MGNT_rmax2]-[MGNT_rmin])/2.

I think CHIMNEY_HOLE_N is too long for an inner opening (and too short for a hole). Or if this is an inner opening, it needs to be bent to much the curvature of the MGNT.

But perhaps, this might not be important in CMSSW. Personally, I prefer this to be fixed because the solid subtraction fails in SketchUp and causes an error. But if this doesn't need to be fixed in CMSSW, I will probably just release some patch from SketchUpCMS/cmssw for SketchUp.

[ktf]

For the record. This will not make CMSSW_5_3_12_patch2 since it was not fully signed before the deadline for it.

[ktf]

After discussing with ianna, this is actually not going into 53X at all. Closing this.