Completed: all eight existing pad Position rules updated in place from Ø5.84 mm to the approved nominal Ø5.08 mm circle, centered at (2.92,0) mm. Live Footprint and Pads-container translations and rotations were zero, so the specified scene positions equal local positions. No pad was recreated. This current result supersedes the historical failed-fit and pending-permission statements below.

The nominal was supplied and independently drawing-reviewed in the approved task: National Semiconductor H08C Rev E, page 22, lead circle Ø4.953–5.207 mm, midpoint Ø5.08 mm. As in the source-evidence section below, this dimensional fact remains unverified by the automated citation service; the linked manufacturer drawing and manual review are the evidence.

All coordinates are mm; Z=0 for every pad. The model leads are unchanged. Exact Position rules were read back successfully. Computed scene output rounds coordinates to 0.0001 mm; the diagonal rows consequently show an apparent 0.00006898 mm discrepancy when calculated from that rounded output, not an unresolved 0.38 mm mismatch. Exact rule-to-nominal center error is below 0.000000001 mm for every pin.

Read-back preserved eight UIDs and pin numbering/assignments, copper size 1.6×1.2 mm for pin 1 and 1.2×1.2 mm for pins 2–8, and the unchanged footprint asset's Ø0.7 mm drills. Only position rules were mutated; no drill, copper, mask, layer, electrical metadata, silk, or source-footprint payload changes were made. The embedded legacy KiCad payload still contains its original circle; the live pad Position rules are the corrected geometry and must be retained.

Model UID a8acbeb9-71c2-4ee1-983c-5450911aa356 remains directly under ROOT with Position 2.92mm 0mm 0.6985mm, rotation 0 0 0, scale 1 and unchanged asset . The package center, pin-1 negative-X orientation, upper-left tab and nominal seating plane are preserved. The simplified external-envelope caveats remain: no glass seals, lead-root enlargement, crown rounding, internal shell, weld detail or markings; no new manufacturer precision is implied.

Fresh top/isometric/bottom read-back confirms body/tab orientation and preserved seating, with all eight leads passing through the corrected holes. Top hides leads; bottom provides the lead-fit view. The slight common-direction apparent displacement of long lead tips in the near-bottom camera is projection, not a radial pad-circle mismatch; exact XY alignment is established by the rule/scene numerical read-back above.

Failed: no assigned mutation or documentation item. Verification limitation: post-mutation DRC validators returned no result (including Invalid Pads); no clean DRC claim. Unattempted/outside scope: manufacturing export qualification, physical assembly tolerance certification, and electrical metadata changes. The approved correction batch and nominal CAD fit are complete, not an assertion of overall manufacturing readiness.

Everything below records the earlier model/seating work and the pre-correction mismatch; its failure and blocked statements are historical, not the current result.

Completed: authored real parametric build123d geometry, compiled/uploaded asset, created a model directly under ROOT as explicitly requested, centered/oriented it to the existing footprint, and inspected top/isometric/bottom renders. Subsequently corrected model seating offset to +0.6985 mm and read back the exact transform plus fresh front/isometric renders. No pads, footprint geometry, or model lead-circle geometry were edited.

Failed / blocked: simultaneous lead-to-hole alignment. Existing TO-5-8 footprint uses a 5.84 mm pitch circle; the H08C drawing specifies 4.953–5.207 mm (nominal model 5.08 mm). No rigid rotation/translation can reconcile the two circles. The model intentionally exposes the mismatch instead of scaling the package or inventing splayed leads. Correct fit requires permission to correct the footprint, or an authoritative assembly lead-form specification. Overall requested fit goal is therefore NOT complete.

Unattempted: pad corrections, invented lead forming, and changes to electrical metadata (outside assigned scope).

Exact asset name: lf155h-h08c.build123d. The asset card offers source and derived STEP/BREP/GLB formats. Pipeline compilation succeeded: 10 solids, 33 faces, volume 261.8539 mm³, bounding size 9.144 × 9.144 × 17.145 mm including untrimmed leads. Source bounds: x/y ±4.572 mm; z −12.7 to +4.445 mm.

The project's supplied four-page military datasheet lists H08CRE on page 4 and refers to attached graphics, but the downloaded PDF ends on that page. The identifier and attachment instruction are machine-verified.

Fallback source: National Semiconductor LF155/LF156/LF256/LF257/LF355/LF356/LF357 family datasheet, physical dimensions page 22, H08C REV E, explicitly listing LF155H. Original manufacturer document hosted by University of Ulm.

Dimensional verification status: the following dimensions were manually transcribed from the actual PDF raster; they remain unverified by the automated datasheet citation service, whose parser mixed the adjacent SOIC drawing into its H08C description. That automated text was not used to size this model. The source image below is the inspection evidence, not an automated fact citation.

Drawing also shows a 0.115–0.145 inch central underside circle, uncontrolled lead diameter up to 0.025 inch, and a lead-control/seating-plane distance of 0.015–0.040 inch below the body reference plane. No depth/material definition is supplied for the central circle; no arbitrary recess or glass-seal depth was invented. Leads use the controlled nominal diameter throughout. The user-requested CAD datum is body underside at z=0 rather than the drawing's lead-control plane. Undimensioned crown rounding, weld seam, internal shell, lead seals and text markings are omitted; this is an external-envelope CAD model, not a detailed manufacturing model. Metal colors are illustrative, not a finish specification.

Existing footprint UID: ff785e57-9d6b-47b0-a3e7-0d11dc700dc2; origin is pad 1, with computed position (0,0,0), rotation (0,0,0), Top side. Pad field is centered at (2.92,0) mm, with center extents x=0…5.84, y=−2.92…+2.92 mm. Embedded KiCad Y was inverted to obtain computed Flux Y-up positions. Pad 1 lies on the negative-X axis relative to the package center, not in a quadrant. The silk tab lies upper-left (+Y,−X from center), along the pin-8 radial direction.

Model node Metal can package v1:

The independent drawing review supplied for this correction identifies the H08C Rev E page 22 seating plane as 0.381–1.016 mm below the flange reference plane (manual drawing evidence; still unverified by the automated citation service). The instructed midpoint is (0.381+1.016)/2 = 0.6985 mm. Moving the model upward by this amount places that nominal seating plane at project z=0 without changing its authored flange datum. This supersedes the earlier interpretation that seating the flange itself at z=0 was correct. This offset is a visualization nominal within the drawing range, not a guaranteed individual package standoff.

Only the model Position rule changed. Read-only rule inspection confirms XY=(2.92,0) mm, rotation 0 0 0, customShapeScale=1, scale=1, scale3d=1, and Asset lf155h-h08c.build123d preserved. ROOT parenting was not mutated. The simplified external envelope, straight controlled-diameter leads, nominal flange thickness, and omitted crown rounding/weld seams/internal shell/seals/markings described above remain unchanged.

Root parenting means this node will not automatically follow later independent footprint movement. This is intentional per the explicit requested hierarchy.

Coordinates are mm in computed Flux frame, after the model's +2.92 mm X translation. Pads have 0.7 mm drill diameters in the unchanged footprint asset. Numeric positions below use the scene tree's displayed precision.

Nominal lead-to-hole radial allowance is (0.7−0.4445)/2 = 0.12775 mm, below every ~0.38 mm error. Even the drawing's maximum 5.207 mm pitch circle and minimum 0.4064 mm lead diameter leave 0.3165 mm radial mismatch versus only 0.1468 mm radial allowance. This is an Error, not merely a nominal tolerance warning. Pin orientation and tab direction are correct; all eight lead centers are radially inward of their holes.

The historical top and bottom renders below confirm centered body, millimeter scale, tab orientation, and inward lead displacement; the historical isometric is retained only as pre-correction evidence and does not verify the corrected seating. Top alone hides leads behind the body, so the bottom view is essential evidence. Fresh post-correction front and isometric views show the flange elevated above the preview plane, with leads extending down; the numerical Position read-back establishes the exact +0.6985 mm offset.

Remaining Error: unchanged Ø5.84 mm pad circle versus Ø5.08 mm nominal lead circle still causes approximately 0.38 mm radial center error at every lead. Seating correction does not fix XY fit. Pad correction or a supported lead-form design remains blocked pending user decision; neither was attempted in this correction batch. This focused seating/documentation batch is complete, but overall fit is not.

The part-project footprint preview is not a complete manufactured PCB assembly. Seating is verified against its z=0 preview plane and source datum, not a fabricated board. Upload thin-feature/unsupported-solid findings are informational for a multi-solid electronic package, not FDM printability requirements. Requested post-mutation DRC validators returned no result, so no clean DRC claim is made. Read-only CAD and numerical fit checks above provide the relevant verification.