Why can't i boole these objects? I want to cut the blades out of the cylinder. It works with some blades, but not all.

For any reason...

Kill alll blades except one
then make Array circular

so now any Booleans functions will works! ;)
http://piloumaison.weebly.com/uploads/3/6/2/0/3620514/werfel.zip

Thanks. Yes, this works. But why?
These "illogical" things make it hard for the beginner (don't get me wrong, i like MOI very much).

hi olle.

If you zoom in on the bevels at the end of each blade there appears to be a crossover of the broad edge of the bevel i.e. the bevel is not a flat plane. One corner appears sharp and the other appears rounded over. The bevel is not properly formed.

I used a straight line to trim of the ends of the blades just above and below the cylinder and then used loft and join to reform the blades as solids(test1.png). The boolean difference operation then worked(test2.png).


Hope this helps.

Cheers
Mal

Hi Olle, just to help clarify, the particular problem looks like an area of "self intersection" near the bottom of the blades. That's where some surfaces of the object criss-cross back over each other, that kind of formation will prevent a solid from having a proper consistent inside and outside region and that can interfere with booleans and intersection calculations.

Here's the area in particular, notice the kind of curly-cue crossing loop:





- Michael

Thanks for explaining. The blades were created with a sweep (flat) and a helix (that was scaled 1D a little bit) as rail.

Hello,

You could also try creating the curve framework using a copy of the rectangle, Helix command, Network each face, Join, then Planar to cap the ends. It results in a better cutting surface with less end ripple. The original is in grey, the Networked in orange.

Hello,

You can further reduce the ripple by rebuilding the construction curves with something like a tolerance of .001 prior to performing the Network command. The original is grey, Networked solid is orange, and the green solid had the Rebuild command run against the curves prior to the Network command.

Thanks to all of You, helped me a lot.