Non-Random "random" start/endpoints

[eldrick 65]

I manufacture some small parts that need to look good, and I have to use Kisslicer instead of Cura, because of a bug in the "random" start/ends on external loops.

The issue, on the part linked below, is that Ultimaker 2 line-start ends are nearly invisible on low layer heights, so placement is not too critical. However, I need to print these parts at .2mm layer height for strength and for a grippy surface, and the start/ends are very visible on the surface at this resolution, particularly with Silver ABS.

That would be OK, if the start/endpoints were randomly distributed and just looked like texture, but the problem is that Cura places the divots in short diagonal segments from 4-10mm long, running up the sides of the part. This is very visible, and looks like the piece has cracks in it.

The net is that whatever algorithm picks the random start/endpoints is badly broken, and needs to be re-done so that the divots are not clustered vertically across layers. I haven't found any way around this with Cura.

Here's the example file:

http://www.clearlyadjustable.com/Temp/1400403_palm4_smalflat.stl

 

[Daid 306]

The net is that whatever algorithm picks the random start/endpoints is badly broken, and needs to be re-done so that the divots are not clustered vertically across layers. I haven't found any way around this with Cura.

 

It's a none-existsing algorithm, so it cannot be broken. Cura picks the clostest point to where it left off, to minimize the amount of movement it needs to do. This indeed usually results in a visible Z scar at 1 point. Instead of the scar scattered across the surface.

 

[eldrick 65]

I think that's perhaps a good strategy only for high-res printers. Even at .16mm layer height it looks pretty awful, particularly on metallic colors.

When printing one-at-a-time, it looks pretty random, except for streaks that appear in several locations per piece.

The other guys all offer random placement at least, and some degree of control over where the pockmarks appear. It's a tradeoff against print time, of course, but can deliver better print quality with fewer visible seam artifacts.

 

[ciclopez 0]

I'm having a similar problem with a shiny material. It would be awesome to be able to choose between the actual method (closest point), a random point method and a method that places the point at corners so its less visible.

 

[eldrick 65]

Almost anything would be an improvement over the current method.

 

[sgt_strife 0]

I think that's perhaps a good strategy only for high-res printers. Even at .16mm layer height it looks pretty awful, particularly on metallic colors.

When printing one-at-a-time, it looks pretty random, except for streaks that appear in several locations per piece.

The other guys all offer random placement at least, and some degree of control over where the pockmarks appear. It's a tradeoff against print time, of course, but can deliver better print quality with fewer visible seam artifacts.

 

Agreed, I use a Fortus 250mc and the software is "Insight" and it has this feature. I know Cura is free, but there are some awesome features that would almost NEED to be added into it and this is for sure one of them.

 

[Daid 306]

there are some awesome features that would almost NEED to be added into it and this is for sure one of them.

 

I pretty much hate it when people say that some "needs" to be done. If I added everything that people told me that was really needed. Then Cura would have been an unwieldy beast. (Not to mention buggy, as it's difficult to implement tons of features without problems)

It's also not a bug if it happens by design.

And, I'm having enough focus issues as it is.

 

[ciclopez 0]

I understand that this is a matter of priorities, and obviously this is not a bug but the way it was designed. We really don't NEED a lot of things that we use in a daily basis, but they are very usefull. I think that this has to be taken as a suggestion, a low priority suggestion that would be very welcome when you have enough time to implement it (if you finally decide to do so)

 

[eldrick 65]

Don't go getting all sensitive on us Daid, these are just suggestions for features that we think would rank Cura higher on the scale of world-class slicers.

Meanwhile, I'll continue to use Kisslicer, now that it has a Sequential printing feature (Beta version).