Hi,
When I try to plot the edge between nodes, the actually color of edge is strange(It seems always the same as background color, so it hard to observe it.) this part of code might be the problem, After change it to
const mrpt::img::TColor col8bit(edge_color >> 8, edge_color & 0x000000ff); It shows the correct default color (0x0000FF40).
The same problem may happends to "edge_rel_poses_color" as well.