From 53f6a28e9ea0fcade41231dd79f08c88a91f8539 Mon Sep 17 00:00:00 2001 From: Sandro Wenzel Date: Tue, 29 Sep 2026 16:36:03 +0200 Subject: [PATCH] Fix the MFT half-disk 3 support pockets to match the drawing This fixes the two large pockets of the MFT half-disk 3 support plate so they match the Subatech drawing. - Each pocket is cut as two TGeoArb8. The left split along f-i left vertex i 0.12 mm inside its piece, so sc_void_1_H*_D3 was non-convex and VecGeom rejects it. - ROOT evaluates that non-convex arb8 as the intersection of its edge half-planes, which left 0.032 cm2 of PEEK inside the left pocket. - On the right, the .02 overlap shift was applied to the corners l and o, so the plate kept a 0.060 cm2 wedge along wall l-m and lost 0.020 cm2 along wall n-o. - Both pockets are now split at y = 7.5 into two convex trapezoids that overlap by .02 away from the walls. https://twiki.cern.ch/twiki/pub/ALICE/MFTWP3/Disk_support_03_05-09-2017.pdf Co-Authored-By: Claude Opus 5.5 --- Detectors/ITSMFT/MFT/base/src/Support.cxx | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/Detectors/ITSMFT/MFT/base/src/Support.cxx b/Detectors/ITSMFT/MFT/base/src/Support.cxx index 856bb86c33c10..d3059e541131f 100644 --- a/Detectors/ITSMFT/MFT/base/src/Support.cxx +++ b/Detectors/ITSMFT/MFT/base/src/Support.cxx @@ -451,12 +451,13 @@ void Support::initParameters() // ### halfdisk 03 mNumberOfVoids[3] = 6; //Number of Voids (big holes) in each halfDisk support mVoidVert[3] = new Double_t[mNumberOfVoids[3]][4][2]{ - {{-21.377, 15.3}, {-20.075, 11.5}, {-17.0, 11.5}, {-17.0, 15.3}}, // a,b,c,d - {{-19.053, 9.5}, {-13.964, 3.5}, {-14.0, 7.5}, {-14.0, 9.5}}, // e,f,i,j - {{-13.964 - .02, 3.5}, {-10.0, 3.5}, {-10.0, 7.5}, {-14.0 - .02, 7.5}}, // f,g,h,i, - {{21.377, 15.3}, {17.0, 15.3}, {17.0, 11.5}, {20.075, 11.5}}, // s,t,q,r - {{19.053, 9.5}, {14.0, 9.5}, {14.0 - .02, 7.5}, {13.964 - .02, 3.5}}, // m,n,o,l - {{13.964, 3.5}, {14.0, 7.5}, {10.0, 7.5}, {10.0, 3.5}} // l,o,p,k + {{-21.377, 15.3}, {-20.075, 11.5}, {-17.0, 11.5}, {-17.0, 15.3}}, // a,b,c,d + // pockets e..j and k..p cut as two convex pieces split at y = 7.5, overlapping by .02; u, u', v, v' lie on e-f and l-m + {{-19.053, 9.5}, {-19.053 + 5.089 * 2.02 / 6., 7.48}, {-14.0, 7.48}, {-14.0, 9.5}}, // e,u',i',j + {{-19.053 + 5.089 / 3., 7.5}, {-13.964, 3.5}, {-10.0, 3.5}, {-10.0, 7.5}}, // u,f,g,h + {{21.377, 15.3}, {17.0, 15.3}, {17.0, 11.5}, {20.075, 11.5}}, // s,t,q,r + {{14.0, 9.5}, {14.0, 7.48}, {19.053 - 5.089 * 2.02 / 6., 7.48}, {19.053, 9.5}}, // n,o',v',m + {{10.0, 7.5}, {10.0, 3.5}, {13.964, 3.5}, {19.053 - 5.089 / 3., 7.5}} // p,k,l,v }; // ### halfdisk 04