diff --git a/modules/mesh/slice raster b/modules/mesh/slice raster
index 63af761413a2bf8754b14a3fec9a6bd1d110af2c..7dea0e5e0f2a68feda9cbd6c4ba8ab317167b839 100644
--- a/modules/mesh/slice raster	
+++ b/modules/mesh/slice raster	
@@ -523,7 +523,7 @@ function worker() {
             if (y0 < y1)
                segs.push({x0:x0,y0:y0,x1:x1,y1:y1})
             else
-               segs.push({x1:x1,y1:y1,x0:x0,y0:y0})
+               segs.push({x0:x1,y0:y1,x1:x0,y1:y0})
             }
          }
       //
@@ -539,7 +539,7 @@ function worker() {
       //
       for (var row = 0; row < h; ++row) {
          var y = ymin+(ymax-ymin)*row/(h-1)
-         rowsegs = segs.filter(p => ((p.y0 <= y) && (p.y1 >= y)))
+         rowsegs = segs.filter(p => ((p.y0 < y) && (p.y1 > y)))
          var xs = rowsegs.map(p => (p.x0+(p.x1-p.x0)*(y-p.y0)/(p.y1-p.y0)))
          xs.sort((a,b) => (a-b))
          for (var col = 0; col < w; ++col) {