Geometry: Reverte purge algorithme to previous version (modified).

src/Model/Geometry/PointXYZ.py

@@ -373,8 +373,8 @@ class PointXYZ(Point):
         c = PointXYZ.distance(p3, p1)
 
         s = float((a + b + c) / 2)
-        res = (
-            s * abs(s - a) * abs(s - b) * abs(s - c)
+        res = abs(
+            s * (s - a) * (s - b) * (s - c)
         ) ** 0.5
 
         return res