garv3
Posts: 2
Joined: Sat Jul 27, 2019 5:52 am

Dense Infill to support Top Solid Layers

Sat Jul 27, 2019 6:16 am

I would love to sea a feature that creates dense support below top solid infill layers.
For example if you print 12 layers with 20% infill, 3 top and bottom layers and the feature parameter set to 20%, the infills would be:
Layer 1: solid
Layer 2: solid
Layer 3: solid
Layer 4: 20%
Layer 5: 20%
Layer 6: 20%
Layer 7: 40%
Layer 8: 60%
Layer 9: 80%
Layer 10: solid
Layer 11: solid
Layer 12: solid

What do you think?

rexipus
Posts: 8
Joined: Mon Aug 05, 2019 9:12 pm

Re: Dense Infill to support Top Solid Layers

Mon Aug 05, 2019 9:45 pm

TL;DR: auto-generated denser infill layers prior to printing top layers over thin air would decrease the number of top layers that must be specified in order to successfully bridge the infill air gaps and get completely filled, non-drooping top layers, saving both printing time and filament usage.

Long version:

I actually came to the forum to post this idea myself. I saw your post, so I'll wholeheartedly support your request instead.

I already do this manually using processes, which is a bit of a pain. In order to reduce the number of top layers that I have to specify in order to get a good, solid, droop-free top, I'll create a new process at the level where I want to introduce a denser infill that will better support the top layers. In order to have the denser infill always include the existing "sparse" infill lines, I make my denser infill an integer multiple of whatever percentage I used for the sparse infill.

Just last night I did a print where I was using 8% infill for most of the print. Two layers before getting to the top I changed it to 32%. This made infill lines that fell on the same lines as the 8% infill, with three more lines in each direction in between those. Yeah, the first layer of extra lines sagged quite a bit and many of the lines were a little broken, but the second 32% infill layer improved this greatly, and by the time I got to my top layers, what was there from the 32% infill (which wasn't perfect by any means) was enough to give the first "top" layer much more to hold onto, with the result that my top layers formed up nicely within two layers or so, not the three or four that would have been required if the first top layer were printing over mostly thin air.

Your suggestion would simply automate this. Here's what I envision:
1) User-specified number of "denser infill" layers.
2) User-specified multiple of the sparse infill percentage, ie: user can specify how dense to make the denser infill layers.

It would be a bonus if we could specify a number of density-boosting "steps," as well as specify how many layers to print at each density step. I'll illustrate by example. Let's say they implement this idea, and the rule for going from sparse to dense infill percentage is to simply double the percentage. Say I set my infill to 10%, and specify two density steps and two layers per step. My print is progressing, and I'm seeing a good 10% infill during the print. When the print gets to four layers before a "top" layer, in that top layer region it changes to 20% infill for two layers, then 40% infill for two layers, then prints the top layers. What's the benefit here? Well, in those four layers under the current sparse infill-only scheme we would see 4x10% = 40% of a single layer's worth of plastic printed in the infill. Adding this new scheme would increase the amount of plastic used so: 2x10% + 2x30% (the difference between what it would have printed at the 10% setting and what it would print under the new setting) for a total of 80% of a single layer's worth of plastic. This 80% worth of a single layer would undoubtedly result in a much better foundation for the "top" layers to print on than simply adding one additional top layer printing over 90% void space. You'd probably have to add at last two or three additional "top" layers to equal the effect in terms of establishing a certain number of successfully printed top layers.

One huge benefit of providing this auto-generated denser infill would be that it only densifies the infill in areas that are directly under upcoming top layers. With my process kludge it's densifying the infill everywhere based simply on the start and stop heights of the process. Look at it this way: Say you're printing a model of a staircase. This illustrates the problem nicely. As you approach each "step" in the staircase you'd like the infill to densify so that the top layers for that step form up more easily with the fewest number of top layers required to do so. You don't want the infill percentage changed in the regions of the models that are under the other steps of the staircase that we haven't reached yet. Doing this manually, with processes, would resulting in densification of the infill across the whole model each time we approached the next step in the staircase. This is wasteful of both time and plastic, not to mention the user's time due to having to add and configure processes at each step in the staircase. In short, adding this feature would be extremely useful, generating the best printing results for the least printing time, filament usage, and time spent dorking around with processes and whatnot in the slicer.

rexipus
Posts: 8
Joined: Mon Aug 05, 2019 9:12 pm

Re: Dense Infill to support Top Solid Layers

Mon Aug 05, 2019 10:02 pm

One thing to remember is that this would be most effective if all of the lines of the existing infill at whatever density you specified are also used by the higher infill percentage, plus whatever new lines come from the higher density.

In your proposed scheme of 20% -> 40% -> 60% -> 80%, you'd lose that benefit in the transition from 40->60% and again from 60->80%. It would be far better to just go 20% -> 40% -> 80%. That way at each level half of the lines of the higher infill percentage are printing onto existing infill lines, and only half would be over thin air.

I also think that going up to 80% is overkill, and if you're going that high you might as well just add extra top layers. In my prints where I used processes to step from 8% to 16% and then 32%, or 10% to 20% to 40% or whatever, the 32% or 40% final "dense" infill layers were enough to provide the first top layer a vastly reduced empty space that it had to bridge over, allowing that first top layer not to be perfect, but to be good enough that by the second top layer it was already pretty solid, and a third or fourth top layer looked more or less perfect. Mission accomplished.

S3D-Jake
Posts: 613
Joined: Wed Jun 20, 2018 12:45 pm

Re: Dense Infill to support Top Solid Layers

Mon Aug 26, 2019 2:17 pm

I love this idea! Thank you so much for posting it. I can think of several use cases where this would be a priceless feature to improve upon the print quality of top surfaces.

Thanks again!
"A bird does not sing because it has an answer. It sings because it has a song."

User avatar
dkightley
Posts: 2059
Joined: Tue Mar 10, 2015 4:09 pm

Re: Dense Infill to support Top Solid Layers

Mon Aug 26, 2019 4:43 pm

I think this is one of two feature requests that, if worked together, would give a superb improvement in slicing....

This feature request viewtopic.php?f=23&t=7906&hilit=infill+perimeter relates to adding of a perimeter around solid infill on top of sparse infill.....which has been reported as a deficiency on many occasions. If this enhancement was addressed in conjunction with the request in this thread, then the end result would be not only a stronger interface between sparse and solid infill, but a reduction in the number of top layers required.

Add these two requests together and you get a 1000+ from me! If you're looking for big hits for v5.....then this is definitely a must-have!
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

wirlybird
Posts: 1221
Joined: Sun Jul 17, 2016 1:32 pm

Re: Dense Infill to support Top Solid Layers

Tue Aug 27, 2019 6:32 am

dkightley wrote:
Mon Aug 26, 2019 4:43 pm
I think this is one of two feature requests that, if worked together, would give a superb improvement in slicing....

This feature request viewtopic.php?f=23&t=7906&hilit=infill+perimeter relates to adding of a perimeter around solid infill on top of sparse infill.....which has been reported as a deficiency on many occasions. If this enhancement was addressed in conjunction with the request in this thread, then the end result would be not only a stronger interface between sparse and solid infill, but a reduction in the number of top layers required.

Add these two requests together and you get a 1000+ from me! If you're looking for big hits for v5.....then this is definitely a must-have!
These are good ideas and especially the boarder/perimeter for the first layer over sparse or any infill for that matter to give the solid layer edges something to grab on to.
But the "dense Infill" layer on top of sparse infill, doesn't this really equate to one additional "solid" top layer? So why not set top layers to 5 instead of 4 for instance?
Is there something that the dense infill layer could do that a solid layer couldn't?

I ask the question because I don't know if we need to add a functionality that we can pretty much already do.

What am I missing on this? And believe me I am all in on dealing with sparse infill!

S3D-Jake
Posts: 613
Joined: Wed Jun 20, 2018 12:45 pm

Re: Dense Infill to support Top Solid Layers

Tue Aug 27, 2019 10:58 am

wirlybird wrote:
Tue Aug 27, 2019 6:32 am
dkightley wrote:
Mon Aug 26, 2019 4:43 pm
I think this is one of two feature requests that, if worked together, would give a superb improvement in slicing....

This feature request viewtopic.php?f=23&t=7906&hilit=infill+perimeter relates to adding of a perimeter around solid infill on top of sparse infill.....which has been reported as a deficiency on many occasions. If this enhancement was addressed in conjunction with the request in this thread, then the end result would be not only a stronger interface between sparse and solid infill, but a reduction in the number of top layers required.

Add these two requests together and you get a 1000+ from me! If you're looking for big hits for v5.....then this is definitely a must-have!
These are good ideas and especially the boarder/perimeter for the first layer over sparse or any infill for that matter to give the solid layer edges something to grab on to.
But the "dense Infill" layer on top of sparse infill, doesn't this really equate to one additional "solid" top layer? So why not set top layers to 5 instead of 4 for instance?
Is there something that the dense infill layer could do that a solid layer couldn't?

I ask the question because I don't know if we need to add a functionality that we can pretty much already do.

What am I missing on this? And believe me I am all in on dealing with sparse infill!
I believe this denser infill before solid layers would be less than 100% fill. So much the same way that dense supports default to 70% rather than 100% fill.
"A bird does not sing because it has an answer. It sings because it has a song."

wirlybird
Posts: 1221
Joined: Sun Jul 17, 2016 1:32 pm

Re: Dense Infill to support Top Solid Layers

Tue Aug 27, 2019 11:16 am

S3D-Jake wrote:
Tue Aug 27, 2019 10:58 am
wirlybird wrote:
Tue Aug 27, 2019 6:32 am
dkightley wrote:
Mon Aug 26, 2019 4:43 pm
I think this is one of two feature requests that, if worked together, would give a superb improvement in slicing....

This feature request viewtopic.php?f=23&t=7906&hilit=infill+perimeter relates to adding of a perimeter around solid infill on top of sparse infill.....which has been reported as a deficiency on many occasions. If this enhancement was addressed in conjunction with the request in this thread, then the end result would be not only a stronger interface between sparse and solid infill, but a reduction in the number of top layers required.

Add these two requests together and you get a 1000+ from me! If you're looking for big hits for v5.....then this is definitely a must-have!
These are good ideas and especially the boarder/perimeter for the first layer over sparse or any infill for that matter to give the solid layer edges something to grab on to.
But the "dense Infill" layer on top of sparse infill, doesn't this really equate to one additional "solid" top layer? So why not set top layers to 5 instead of 4 for instance?
Is there something that the dense infill layer could do that a solid layer couldn't?

I ask the question because I don't know if we need to add a functionality that we can pretty much already do.

What am I missing on this? And believe me I am all in on dealing with sparse infill!
I believe this denser infill before solid layers would be less than 100% fill. So much the same way that dense supports default to 70% rather than 100% fill.
Will this add any tangible bennifit that increasing the top solid layer count by 1 doesn't accomplish?

S3D-Jake
Posts: 613
Joined: Wed Jun 20, 2018 12:45 pm

Re: Dense Infill to support Top Solid Layers

Tue Aug 27, 2019 11:24 am

It would definitely result in less filament being used but with a similar surface improvement to that of adding an additional top solid layer. Sounds like a win - win situation to me!
"A bird does not sing because it has an answer. It sings because it has a song."

wirlybird
Posts: 1221
Joined: Sun Jul 17, 2016 1:32 pm

Re: Dense Infill to support Top Solid Layers

Tue Aug 27, 2019 11:44 am

S3D-Jake wrote:
Tue Aug 27, 2019 11:24 am
It would definitely result in less filament being used but with a similar surface improvement to that of adding an additional top solid layer. Sounds like a win - win situation to me!
I think the filament savings between 70% and 100% is negligible and personally I'd probably set it to 100% anyway.

The concept is good but if the only thing this feature would do is add a "solid" below the top solid layers then there is no point for a feature that does what can already be done with minimal effort.

Now, if the feature for a dense layer adds items such as-
path direction/angle so you could set a unique angle and not just default to the solid infill angle.
Speed
Extrusion width
bounding perimeter(s)
expand past default size like in bridging.

Things like this might make it an actual functional feature rather than just another way to do what can already be done easily.

Some thoughts.

Return to “Feature Requests”