Bug in bridge settings

[cheme 0]

I am using Cura 3.4.1.  I was attempting to slice with the Enable Bridge Settings box checked with the following settings:

 - Minimum Bridge Wall Length:     0.4 mm

 - Bridge Skin Support Threshold:     50%

 - Bridge Wall Max Overhang:     55%

 - Bridge Wall Speed:     12 mm/s

 - Bridge Skin Speed:     12 mm/s

 - Bridge Fan Speed:     100%

 - All other settings:  default

The model that I was attempting to slice was the Salt Lake Temple on Thingiverse by hlyman.

Using a 0.2 mm layer height, I found that there were holes in the walls on some layers.  Also some of the outer wall locations were changed.  When I deselected the Enable Bridge Settings, the problem went away.

Any suggestions on a workaround to still be able to use the bridge settings and not have the holes in the walls, etc.?

 

 

[kmanstudios 1,120]

Just out of curiosity, what printer were you slicing for? I have no experience with the bridge stuff, but wonder if there is a bug you found, or if it is not slicing for a 3rd party printer properly.

 

Always good to learn something new.

[cheme 0]

17 minutes ago, kmanstudios said:

Just out of curiosity, what printer were you slicing for? I have no experience with the bridge stuff, but wonder if there is a bug you found, or if it is not slicing for a 3rd party printer properly.

 

Always good to learn something new.

I am using a Monoprice Maker Select Plus printer.

[kmanstudios 1,120]

Thanks ? That will give the people in the know a better chance of sussing this out ? That means just about anybody but me...?

[burtoogle 513]

8 hours ago, cheme said:

Using a 0.2 mm layer height, I found that there were holes in the walls on some layers.  Also some of the outer wall locations were changed.

 

Hi @cheme, could you please post a screen shot (or photo) showing the holes, I have sliced this and cannot see any  obvious problems. Also, what size did you scale the model to? It's very small, you must have scaled it up?

Edited September 4, 2018 by burtoogle

[burtoogle 513]

I am guessing that you are referring to the regions where the outer wall lines have coasted immediately before a bridge line as you can see in this picture.

 

 

You can see the coasting to the left of the tops of the arched windows. This is normal when using the bridging settings. The reasoning behind the coasting is to reduce the over-extrusion that often occurs at the start of a bridge line due to the step change in extrusion rate that occurs when going from a normal wall line to a thin and/or slow wall line. The coasting looks bad in the layer view but when the model is printed it doesn't normally appear as a hole. However, if you are seeing holes due to the coasting, just reduce it (all the way to 0% if you wish).

 

What looks like long holes above the windows is the bottom of an overhung region which you can see in the solid view.

 

 

Again, I don't think what I am seeing in the layer view is wrong but I would have to print it to be sure. Do you have photos showing the problems in the printed model?