Layers removed when I scale/rotate?

[searaider2 0]

Hello all.

So I am loading a .OBJ file into cura. The object is very small, so I am forced to uniformly upscale. When I do so, the object's layers are being created correctly at certain scale values, but at others (most) the layers seem to be arbitrarily disappearing.

Scaling up to 20... Works.

Scaling up to 50... Doesn't work.

Scaling up to 50... With a slight rotation.. Seems to kind of work all the sudden?

Any thoughts as to why this may be happening?

Edited June 6, 2017 by Guest

[gr5 2,071]

Hmm. Usually this is because of thin walls but these look pretty thick. I'm guessing the model has lots of holes in it and sometimes those holes line up with a layer. Cura is called a "slicer" for a good reason. It starts each layer by intersecting a plane with the triangles found in the STL or obj file. Each intersection results in a line. Cura tries to combine those lines into loops for a given layer. Sometimes the loops have holes or openings because the object you are modeling has holes in it.

If the holes are very small then scaling the part slightly moves where the lines hit the holes.

Try looking at the part in xray view and look for tiny red spots (zoom way in). The red indicates something wrong with the model (either internal walls or holes on the "surface").

[kmanstudios 1,120]

Also, where did the model come from? I hear a lot of people having trouble with some programs such as Sketchup.