PrusaSlicer supports not touching ramp
 
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Ari
 Ari
(@ari-4)
Active Member
PrusaSlicer supports not touching ramp

Can someone tell me if this is a bug in PrusaSlicer? Is there some setting I missed? FWIW, this behavior is the same in PrusaSlicer 2.2.0 (final) and 2.3 alpha-3.

I was trying to support a 26 degree ramp (74 degree overhang?) so added supports using support enforcers, but the resulting supports don't actually touch/support the ramp and the underside came out pretty lousy as a result. The object shown here is simplified; I can't print the actual object on its side, so I'm really wondering if there is a way to support the current orientation.

In the first image, below you can see the gap. It appears to be controlled by XY Separation gap (i.e. the larger the number the larger the gap to the ramp). Here I set it to 150%, which I had done partly to keep things away from vertical walls. The gap is still there even at 50%, just smaller. (Contact Z distance has no effect on this.)

In the second image, you can see proper contact with horizontal surfaces on the same object. Third image is the contact enforcer used to generate the supports.

 

Ramp with non-support

Horizontal is OK

Support enforcer spec

Posted : 13/11/2020 9:03 pm
Ari
 Ari
(@ari-4)
Active Member
Topic starter answered:
RE: PrusaSlicer supports not touching ramp

Just figured out how to add a 3MF file (or at least one way?), in case people want to try it out themselves. Here's the zipped file:

test supports

Posted : 13/11/2020 9:18 pm
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Illustrious Member
RE: PrusaSlicer supports not touching ramp

It looks like the slicer is doing exactly what you've told it to do. Keep 150% away from any vertical wall or step. This applies to vertical and diagonal surfaces. Slicer appears to be overriding the vertical gap setting in favor of the wall gap setting. It might have something to do with directionality of the various extrusions.

I'd align the support to be 45 or 90 degrees to the bottom layers rather that parallel. And, when I did that, things appear to behave better.

Try setting support alignment to 90 degrees.

Posted : 14/11/2020 4:33 am
Ari
 Ari
(@ari-4)
Active Member
Topic starter answered:
RE: PrusaSlicer supports not touching ramp

@tim-m30

Thanks @tim-m30. But can you help me again? I can't seem to reproduce what you wrote. First, the ramp is a straight line before slicing - there's no stair-stepping in the original model. But more important, no matter what angle I use for "Support Material -> Pattern Angle" (in the Print Settings tab) there is a gap. You do have to align the view to see the gap (and using a large XY separation makes it easier to see). Alternatively, notice that there are no blue lines/extrusions under the ramp after slicing (blue = overhang perimeter: you can see it under the horizontal overhang in my second image above). In fact, in the first image you can see that the support extrusions are, in fact, perpendicular to the body extrusions. Setting Pattern Angle to 90 degrees makes the supports parallel -- and whether it's 0, 45, or 90 degrees, there's no contact with the underside of the ramp. 

Did you mean for me to change a different parameter?

 

Posted : 14/11/2020 7:11 am
Ari
 Ari
(@ari-4)
Active Member
Topic starter answered:
RE: PrusaSlicer supports not touching ramp

Oops, the following statement is wrong. My bad! It doesn't affect the question though, just makes it harder to visualize the in/correct behavior.

Alternatively, notice that there are no blue lines/extrusions under the ramp after slicing (blue = overhang perimeter: you can see it under the horizontal overhang in my second image above).

Posted : 14/11/2020 7:31 am
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