+
+
Figure 1: triangulation; grey lines are triangle edges; yellow lines + are three 2nets to route +
+
-TODO: img tri.lht +
+
+
Figure 1: triangulation; grey lines are triangle edges; yellow lines + are three 2nets to route +
+
Furthermore each 2net has a required geometry (wire thickness and clearance), and edges have physical lengths. Local congestion is avoided by @@ -49,7 +55,13 @@ to physical geometry, introducing new edges (spokes) and moving the 2net-edge crossing points on the edge without changing the order of them.
-TODO: img 3net.lht +
+
+
Figure 2: three networks routed; first the two horizontal ones then + the vertical one +
+
This document focuses on the TRBS step. @@ -119,7 +131,13 @@ endpoint are the same. Main input is the enter point or vertex. Other input is a target edge or target vertex within the same triangle.
-TODO: passthru1 +
+
+
Figure 3: edge-to-edge visibility in a triangle; annotations are + drawn with red, existing paths with blue +
+
In case of target edge, the output is a point on that edge (which topologically means the index on the edge's crossing list, where the new crossing is to be @@ -128,8 +146,6 @@
The algorithm for determining visibility is:
-TODO: image passthru1 -
-TODO: image passthru2 +
+
+
Figure 4: blue and green nets starting from triangle vertices, still + S2 finds its target edge point +
+
A CW search from S2 first reaches vertex PA then will jump to the edge PA-PC, which is the target edge. @@ -175,7 +197,12 @@
Case 3: visibility blocked
-TODO: image passthru3 +
+
+
Figure 5: target edge not visible from S2 because of an existing path +
+
Starting from S2, tracing CCW: trace S2's edge to PB, then switch edge by 3c, bumping into the blue path by 4, tracing it to edge PA-PB;