RevK
Posts: 2
Joined: Thu Feb 09, 2017 3:36 pm

Bridging issues.

Thu Feb 09, 2017 3:46 pm

http://www.thingiverse.com/thing:44579 is a good example of a box that has a top which needs bridging. The bridging works fine on Makerbot and Cura, but on Simplify 3D it insists on drawing the perimeter lines before considering bridging. This means the bridging is in thin air and simply does not work.

Also, when modified design to have thicker walls, one side of the fill is absent, i.e. three sided area being filled. However, in some cases, the bridging is not side to side from the supported wall to the supported wall, but diagonal from a supported wall to a strange forming the new edge. Surely the fill direction logic needs to consider if the side in question is supported or not, and try to pick fills direction that aims for properly supported ends to all of the bridge lines.

CompoundCarl
Posts: 2005
Joined: Wed Aug 05, 2015 7:23 am

Re: Bridging issues.

Fri Feb 10, 2017 8:24 am

If might help if you post a factory file for the second part of your question. That will make it much easier for people to give suggestions.

slider162
Posts: 1
Joined: Wed Feb 15, 2017 3:08 pm

Re: Bridging issues.

Tue Feb 21, 2017 9:36 am

Here is a good one that will showcase S3Ds bridging weaknesses. S3D wants to bridge lengthwise.

http://www.thingiverse.com/thing:1753983

I couldn't print the duct using S3D with PLA, ABS, or PETG. Also had horrible delamination but that may just be user error. I got tired of trying to print this one and made my own with thicker walls and fillets galore.

dgiller
Posts: 4
Joined: Tue Sep 27, 2016 12:27 pm

Re: Bridging issues.

Fri Mar 10, 2017 3:21 am

S3D's printing of support material is excellent and you can fix most things with manual support when you need to. But sadly its bridging is still quite poor. The problem is, you can't always use supports under your bridges.

Even the current version prints the outlines of a bridge at full speed, ignoring any bridging parameters, and it likes to run the bridge layer the long way along a bridged section between the just-printed outlines (which failed because they were printed without the bridge speed and fan settings), rather than the shortest way across a bridge to the already-solidified walls. Duct-like parts like Thing 1753983 do illustrate the problem well.

When your part has a bridge made entirely of outlines, such as a cutout in a thin wall, it's hopeless if it's more than a few mm across.

I have seen people complaining about this for at least two years, and nothing has been done about it.

If they fixed S3D so that it applies the bridging speed multiplier to the outlines that cross a bridge instead of just the infill, it would go a long way toward improving the situation, but even that has not happened yet.

brian442
Posts: 1243
Joined: Mon Nov 28, 2016 5:35 am

Re: Bridging issues.

Fri Mar 10, 2017 5:30 am

The duct part that you posted (1753983) has walls that are only about 1 extrusion width wide. So when you get to the top layers, there is nothing actually below the bridging layers that it can grab onto. So that isn't really a good test. Bridging is meant to go from one foundation to another, and in this case there is no foundation at all. You would need to use support material if you wanted to print it correctly.

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