diff --git a/gitnexus-web/src/hooks/useSigma.ts b/gitnexus-web/src/hooks/useSigma.ts
index e24d3a376..0bf48c5f4 100644
--- a/gitnexus-web/src/hooks/useSigma.ts
+++ b/gitnexus-web/src/hooks/useSigma.ts
@@ -1311,7 +1311,6 @@ export const useSigma = (options: UseSigmaOptions = {}): UseSigmaReturn => {
             const targetR = ringTargetR[Math.min(ring, CIRCLES_RING_COUNT - 1)];
             const x = attrs.x;
             const y = attrs.y;
-            const r = Math.sqrt(x * x + y * y) || 1;
 
             // Soft-wall gravity (force 1) already handles radial boundary
             // enforcement — no separate resistance decomposition needed.
diff --git a/gitnexus-web/src/lib/tree-layout.ts b/gitnexus-web/src/lib/tree-layout.ts
index c713c0bb0..5fb284d5c 100644
--- a/gitnexus-web/src/lib/tree-layout.ts
+++ b/gitnexus-web/src/lib/tree-layout.ts
@@ -501,7 +501,11 @@ export function calculateTreeLayout(graph: KnowledgeGraph): Map<string, TreeNode
 
   // 6. Relax the graph like a constrained spring system. Only X is allowed
   // to move, so node types stay on their original Y layers.
-  const SPRING_ITERATIONS = 14;
+  // For large graphs the spring phase is O(N×E×iterations) and would freeze
+  // the main thread — scale it down proportionally so the initial proportional
+  // layout (already good at large N) is kept without expensive refinement.
+  const nodeCount = graph.nodes.length;
+  const SPRING_ITERATIONS = nodeCount > 10000 ? 0 : nodeCount > 3000 ? 4 : 14;
   for (let iter = 0; iter < SPRING_ITERATIONS; iter++) {
     const deltaXByNode = new Map<string, number>();