It's taken me a while to boil this down to simple example code, but here it is. module Part1 () { color ("red") union () { cube ([10, 20, 30], center=true); cylinder (r=8, h=60, center=true); } } module Part2 () { color ("white") difference () { sphere (r=15); rotate ([0, 0, 0]) cube ([10, 20, 30], center=true); // Rotate me and see what happens to colours! } } Part1 (); Part2 (); Part1 is a union of a cube(oid) and a cylinder. It's red. Part2 is a sphere with a cuboid removed. It's white. When the two cubiods are (close to) incident, the colour of Part2 "bleeds" into Part 1. This means that my complex objects that do a lot of adding and subtracting of common underlying elements can't be coloured. Known issue? Open bug? Me being stupid?

On 2017-08-09 14:05, Gadgetmind wrote: > > When the two cubiods are (close to) incident, the colour of Part2 > "bleeds" into Part 1. This means that my complex objects that do a lot > of adding and subtracting of common underlying elements can't be coloured. > Hmmm, this might be this issue. https://github.com/openscad/openscad/issues/1000 Sadly, adding render() in various places gives me a 5 minute preview time on my model even with just 5% of it being drawn and at low "resolution".

On 2017-08-09 14:05, Gadgetmind wrote: > > When the two cubiods are (close to) incident, the colour of Part2 > "bleeds" into Part 1. This means that my complex objects that do a lot > of adding and subtracting of common underlying elements can't be coloured. > Hmmm, this might be this issue. https://github.com/openscad/openscad/issues/1000 Sadly, adding render() in various places gives me a 5 minute preview time on my model even with just 5% of it being drawn and at low "resolution".