PrusaSlicer 2.2.0-alpha4 - Interesting internal bridging
 

PrusaSlicer 2.2.0-alpha4 - Interesting internal bridging  

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bobstro
(@bobstro)
Famed Member

I noticed some unexpected bridging effects while playing around with the D6 dice model that was linked to in another thread. I first noticed that the top hole had bridging across the top hole, providing a nice "sacrificial support" feature. Experimenting with this, I cut the part in half and noticed that this bridging no longer occurred if the part was open at the bottom (view from underside):

This is different than with 2.1.1 (view from top):

This would be a handy feature for using larger extrusion sizes. Here's a test print using a 0.50mm nozzle. You can see the heavy extrusions sag badly around the opening:

I tried to replicate this effect by closing off the bottom of my otherwise-hollow test puzzle part:

Does anybody have any idea:

  1. What might trigger this bridging on the dice shape but not my test part? 
  2. What changed from 2.1.1?
  3. How we might harness and selectively enable this bridging?

 

This topic was modified 1 month ago by bobstro
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 20/02/2020 4:20 am
bobstro
(@bobstro)
Famed Member

3MF project attached for anybody wanting to experiment. For some reason, the cut die is now bridging just like under PrusaSlicer 2.1.1, so I'm really puzzled as to what's going on.

Edit: Just realized the STL from Thingiverse has the sacrificial bridge built in... but it disappeared when I cut it apart. Now I'm really puzzled.

This post was modified 1 month ago by bobstro
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 20/02/2020 4:29 am
bobstro
(@bobstro)
Famed Member

Here's the 3MF with the disappearing bridge. I only cut the part and this happened. Have not been able to replicate this though. I suppose it's technically a bug in 2.2.0-alpha 4, but not sure what triggered it.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 20/02/2020 4:37 am
chocki
(@chocki)
Prominent Member

Can we use a modifier to create internal bridging like in the model?, this could be a very handy feature.

And, maybe I just don't know how or it does not exist yet, when I slice a model I check the layers in the preview for any issues, this usually involves zooming in and tilt / rotating the view, is it possible to pan the view? as this would be very handy indeed and allow for some good fine tuning of settings / supports etc etc.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet....
Posted : 20/02/2020 7:29 am
Neophyl
(@neophyl)
Honorable Member

@chocki

You can use a modifier and set it to 1 layer height and place them where you want to fill in areas yes.

As for panning, while its not quite perfect yet the recent added support for the 3dconnexion space mouse range allows that sort of movement as its a 6dof (6 degrees of freedom) input device.

You can also right click and drag to pan around an area too.  The one function that is lacking is a sort of xray mode, which would be useful in allowing placement of modifiers inside of models.  At the moment its a bit hit and miss and you can lose sight of small modifiers inside a model completely.

Might just go add a feature request for that one 🙂

Posted : 20/02/2020 8:29 am
chocki
(@chocki)
Prominent Member

Doh - Didn't think of using right click, and Hooray, I have a space mouse 🙂

The X ray feature, do you think it could work by using transparency for the existing model? 🙂

 

Thanks.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet....
Posted : 20/02/2020 10:52 am
Neophyl
(@neophyl)
Honorable Member

Always willing to pick up new tricks with Slicer, is there already some form of transparency for models that I've missed ?

Posted : 20/02/2020 11:02 am
Lichtjaeger
(@lichtjaeger)
Prominent Member

Maybe you cut to a ½ layer? The bridge might not be realized when it is not a full layer thick.

Try to switch to 0.1 layer height and look if it is back.

Posted : 20/02/2020 11:29 am
chocki
(@chocki)
Prominent Member
Posted by: @neophyl

Always willing to pick up new tricks with Slicer, is there already some form of transparency for models that I've missed ?

No, that's my suggestion, if your already putting one in for X-Ray, then suggest variable transparency as this would help with placing modifiers.

 

And where do you put suggestions in?.

This post was modified 1 month ago by chocki
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet....
Posted : 20/02/2020 12:06 pm
Neophyl
(@neophyl)
Honorable Member

@chocki

That's what I mean by x-ray anyway, not to be confused with wireframe :).  So it would also help with duplicate part placement as it would shade darker where parts intersect, you would be able to tell that parts were duplicated.  

You just add them to github same as a normal bug report.  Every so often one of the devs goes through and adds tags on to issues.  I've already added it over there but if anyone wants to pile on and raise its profile as 'a good idea' feel free 🙂

Posted : 20/02/2020 12:35 pm
chocki
(@chocki)
Prominent Member

Great, I will look into this tomorrow now, have to be up very early, and the printers still got 1Hr 35 to finish, I hope I can sleep.

Finally building a LACK enclosure.

Should have used a 0.6mm nozzle.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet....
Posted : 20/02/2020 8:25 pm
Neophyl
(@neophyl)
Honorable Member

I pretty much leave the 0.6 nozzle on my heavily modded direct drive cr10 now for 'draft' and quick prints and use the 0.4 on my mk3 for ones that need the better quality.

I built the enclosure when I first got my mk3 but I was looking at a remix that has doors that you can open up and then slide inside to get them out the way.  Useful when you need to leave them open for pla prints.  Cant seem to find the time to reprint though lol.

Posted : 20/02/2020 8:32 pm
bobstro
(@bobstro)
Famed Member
Posted by: @lichtjaeger

Maybe you cut to a ½ layer? The bridge might not be realized when it is not a full layer thick.

Thought that might be it, but the cut part has a good gap between the print bed and underside of the top surface.

Try to switch to 0.1 layer height and look if it is back.

I can't seem to re-create the effect that caused it to disappear. At this point, I think it was just a glitch. I was hoping there was a "bridge small openings" feature I'd missed, but it doesn't appear so.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 20/02/2020 8:45 pm
Sembazuru
(@sembazuru)
Honorable Member
Posted by: @bobstro

[...]

I was hoping there was a "bridge small openings" feature I'd missed, but it doesn't appear so.

Oh, a bridge small openings (possibly with an adjustable threshold) feature would save me a bundle of time adding flattened cylinder parts to my prints to manually bridge vertical screw holes. A concept that I picked up from Makers Muse (I think...) and applied with the PrusaSlicer toolset.

See my (limited) designs on:
PrusaPrinters - https://www.prusaprinters.org/social/1448-sembazuru/prints
Thingiverse - https://www.thingiverse.com/Sembazuru/designs...
Posted : 20/02/2020 9:53 pm
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