I am becoming increasingly frustrated with S3D, which is a pity as I like it generally. I am trying to print with 2 tools and am getting a problem when the tool changes. On the first change there is no issue, but subsequent changes I get a huge over extrusion causing a large blob as the new tool starts to print. Looking at the gcode S3d is generating I can see what is wrong but cannot work out why. As the first tool prints all goes well until it comes to change to the next tool. When this happens I get a retraction before the change (see below) G1 E-5.0000 F3000 The tool then changes and after wiping and moving to the start point I get an extrusion (see below) G1 E5.0000 F3000 My retraction is set to 0.5mm, I have a zero extra restart distance and a retraction speed of 2400mm/min so I have no idea where this has come from. During normal printing with one tool all retractions are handled OK, it is only when the tool changes that this appears. Can someone please help before all my hair disappears. Thanks. PS. This has raised a couple of other issues with the way S3D works but I will stick to one at a time so as not to overcomplicate things.