From c00ee3d924992d586e5bda1af24fe049b9864ec1 Mon Sep 17 00:00:00 2001
From: Hakan Seven <hakanseven8125@gmail.com>
Date: Tue, 11 Aug 2026 10:17:22 +0300
Subject: [PATCH] fix(acis): use source fit tolerance

---
 Cargo.lock                       |  2 +-
 Cargo.toml                       |  2 +-
 src/scene/convert/acis_kernel.rs | 20 +++++++++++++++-----
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a38224977..2a5171fa5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -890,7 +890,7 @@ checksum = "fc652a48c352aef3ea3aed32080501cf3ef6ed5da78602a020c991775b0aff04"
 [[package]]
 name = "cadkernel"
 version = "0.1.0"
-source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=71e2af6#71e2af6bff7adeb115368cc665842ee51a058014"
+source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=584695a#584695a37dfd420e1e2d4502233c5dfd99fba472"
 dependencies = [
  "acadrust",
  "cavalier_contours",
diff --git a/Cargo.toml b/Cargo.toml
index 225eb50bf..348ecacc2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,7 +32,7 @@ rfd = "0.17"
 clap = { version = "4", features = ["derive"] }
 env_logger = "0.11"
 acadrust = { git = "https://github.com/HakanSeven12/cadcodec.git", rev = "7e2fa8c", features = ["serde"] }
-cadkernel = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "71e2af6", features = ["acis", "offset"] }
+cadkernel = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "584695a", features = ["acis", "offset"] }
 acadifc = { git = "https://github.com/OpenAEC-Foundation/acadifc.git", rev = "47b5603", optional = true }
 dwg-thumbnailer = { path = "crates/dwg-thumbnailer" }
 flate2 = "1"
diff --git a/src/scene/convert/acis_kernel.rs b/src/scene/convert/acis_kernel.rs
index 8a5cfb645..5e5acf6ba 100644
--- a/src/scene/convert/acis_kernel.rs
+++ b/src/scene/convert/acis_kernel.rs
@@ -15,8 +15,7 @@ use cadkernel::brep;
 use crate::scene::convert::solid3d_tess::{body_transform, finalize_mesh};
 use crate::scene::model::mesh_model::{CurvedGen, MeshLodSet};
 
-/// ACIS topology fit tolerance.
-const TOL: f64 = 1e-6;
+const DEFAULT_FIT_TOLERANCE: f64 = 1e-6;
 
 /// Tessellate an ACIS document through the kernel.
 pub fn tessellate_sat(
@@ -34,6 +33,7 @@ pub fn tessellate_sat(
     for body in bodies {
         let source = body.provenance.source()?;
         let transform = body_transform(document, source.index() as usize).ok()?;
+        let placement_scale = transform.map_or(1.0, |(_, _, scale)| scale.abs());
         let placed = if let Some((matrix, translation, scale)) = transform {
             let placement = brep::Placement {
                 x_axis: [scale * matrix[0], scale * matrix[1], scale * matrix[2]],
@@ -45,7 +45,7 @@ pub fn tessellate_sat(
         } else {
             body
         };
-        placed_bodies.push(placed);
+        placed_bodies.push((placed, placement_scale));
     }
     let bodies = placed_bodies;
     let resolution = if facet_res.is_finite() && facet_res > 0.0 {
@@ -98,9 +98,19 @@ pub fn tessellate_sat(
     // parameters leaves a hole, the same as one that never lifted — so both
     // are counted before calling the mesh whole.
     let mut undrawn = 0usize;
-    let tolerance = brep::mesh::TessellationTolerance::new(max_angle, TOL)
+    let source_fit = if document.header.spatial_resolution.is_finite()
+        && document.header.spatial_resolution > 0.0
+    {
+        document.header.spatial_resolution
+    } else {
+        DEFAULT_FIT_TOLERANCE
+    };
+    for (body, placement_scale) in &bodies {
+        let tolerance = brep::mesh::TessellationTolerance::new(
+            max_angle,
+            source_fit * placement_scale,
+        )
         .with_isolines(isolines);
-    for body in &bodies {
         let tessellation = brep::mesh::tessellate(body, tolerance);
         undrawn += tessellation.missing_faces.len();
         for face in &tessellation.triangle_faces {