I’m a beginner in grasshopper and trying to learn how to use. I’ve just started to do a new study and tried to use the ‘solid difference’, but it’s not working and I can’t understand why. Anyone could help?
Grasshopper file is also attached
Thanks
SteppedBuilding.gh (40.1 KB)
i forget if solid difference works with surfaces… regardless, you will likely need to extend the cutting object a little bit in both directions to avoid coplanar surfaces between the cutting object and the object to be cut
The reason your difference is not working is that the surface normals of your cutter objects need to be flipped. Boolean operations use the normal direction to indicate the outside of the objects involved. With a closed object this is a no brainer, but for an open object like yours Rhino has no way to know which is the outside so may get it wrong.
Because the two objects involved in your difference have opposite normals what is actually happening is that they are being unioned rather than differenced. Flipping one object’s normals so that they both point the same way at the coincident surface gives you the difference you are seeking. If booleaning with open objects you must always explicitly handle the normal directions, whether in Grasshopper or Rhino.
HTH
Jeremy
