Support depending on alignment?

[dirkdirk 5]

HI,

is it normal that the supports in cura are depending on the alignment of the model?

I tried to record this on a short clip.

http://youtu.be/Csf7mxhvja8

Thank you

 

[dirkdirk 5]

Nobody has the same problem?

[Titus 170]

Actually, perhaps. I noticed some strange support behaviour. In a symmetrical part, it would do the left side, but not the right side. I havn't tried rotating the part though...

 

[Daid 298]

The support is generated with a projected bitmap. Which causes these kinds of artifacts.

 

[dirkdirk 5]

The support is generated with a projected bitmap. Which causes these kinds of artifacts.

 

Maybe you could explain this for my? I do not understand how the same model is supported different depending on alignment?

So i have to check every possible alignment before printing for best supports?

[Daid 298]

Maybe you could explain this for my? I do not understand how the same model is supported different depending on alignment?

So i have to check every possible alignment before printing for best supports?

 

What Cura does, is kinda like this:

So it takes the object. Looks from the top. However, it does this at a lower resolution. In the last picture, if there is enough purple, support is added there.

Some smoothing is done on the final support. And the resolution at which this is done is actually higher then what I show here, but I hope it helps in understanding what is happening.

 

[Dim3nsioneer 540]

Pretty cool demonstration! :cool: It could be called 'inside Cura'...

 

[kolia 31]

I feel a little dumb now but I don't see why a projected bitmap from top would be different when he is rotating the part on plane parallel to the bed? Or is it related to the "squares" background? Even so, it is hidden by the part...

I hate when I don't get it =) (especially when 2 people like your answer Daid -unless they just pretended understanding it :-p-)

 

[Daid 298]

Location from where the pixel map is generate is always the corner of the outer box of the object, this causes the "pixels" to align differently on the model.

Simply put, it's an aliasing problem.

 

[kolia 31]

I think I understand, but then shouldn't it be minor artifacts? On Dirk video it's like a full side of the part not being (or being) supported, looks big for an "aliasing" problem?