ururk
Posts: 25
Joined: Thu Apr 16, 2015 10:21 pm

Impossible slice?

Mon Jun 04, 2018 3:59 pm

I'd like to slice a cube such that when sliced, it will look like I cut a cube from one of the corners. I can mimic this somewhat with multiple processes:
cube.png
But the perimeters on the inside shouldn't print. Any thoughts? I tried switching to relative positioning and editing the gcode, but it is beyond my abilities at this point.

Thanks!

TheBum
Posts: 50
Joined: Fri May 18, 2018 10:13 pm

Re: Impossible slice?

Mon Jun 04, 2018 6:40 pm

Are you looking for it to be solid where the cuts are? If so, you're better off using Meshmixer or similar to modify the model. You can do three plane cuts to isolate the corner you don't want and then do joins to reattach the other portions.

ururk
Posts: 25
Joined: Thu Apr 16, 2015 10:21 pm

Re: Impossible slice?

Mon Jun 04, 2018 7:08 pm

Imagine I printed a solid cube (25% infill). I then cut a cube out of the cube with a power tool (ie, dremel). You would see the top honeycomb pattern, as well as the infill from the side.

darkoses
Posts: 2
Joined: Sun Mar 04, 2018 12:35 pm

Re: Impossible slice?

Mon Jun 04, 2018 10:12 pm

It sounds to me like you want to do a multiple process print with no top layers on the first process and top layers on the second process. Not sure how to get the infill shown on just the one side wall.. my guess is you may have to model it that way or truly cut it.

ururk
Posts: 25
Joined: Thu Apr 16, 2015 10:21 pm

Re: Impossible slice?

Tue Jun 05, 2018 9:32 am

darkoses wrote: It sounds to me like you want to do a multiple process print with no top layers on the first process and top layers on the second process. Not sure how to get the infill shown on just the one side wall.. my guess is you may have to model it that way or truly cut it.
Yeah, I'm already doing that to prevent the top layer from printing, but I don't think there is a way to avoid a full perimeter. I probably need to manually modify the g-code to replace the perimeters on the inside and replace them with rapid travel movements.

I was trying to avoid dremeling the part, can't think of a different way to do this. I'm not too sure how infill without a perimeter will print anyhow, with nothing to stick to it might just shrivel away.

RoboDLC
Posts: 49
Joined: Sun Apr 23, 2017 1:30 am

Re: Impossible slice?

Mon Jun 11, 2018 12:25 pm

ururk wrote:
Tue Jun 05, 2018 9:32 am
darkoses wrote: It sounds to me like you want to do a multiple process print with no top layers on the first process and top layers on the second process. Not sure how to get the infill shown on just the one side wall.. my guess is you may have to model it that way or truly cut it.
Yeah, I'm already doing that to prevent the top layer from printing, but I don't think there is a way to avoid a full perimeter. I probably need to manually modify the g-code to replace the perimeters on the inside and replace them with rapid travel movements.

I was trying to avoid dremeling the part, can't think of a different way to do this. I'm not too sure how infill without a perimeter will print anyhow, with nothing to stick to it might just shrivel away.
I would do this with two models and two processes. The first model would be the bottom part, have that process print with 0 top layers. the second model would start where the first model left off, print with no bottom layers and finish the job for the top layers. This second model would have your corner cut out.

Use TinkerCAD ('cause its easy') and build your two models there. before you export the two models, move them together so that they look like your final part and share the same reference "zero". Export the two halves separately as STL files. Any CAD package should allow this, but TinkerCAD makes it trivial.

Import the two models into S3D, select both models, do edit->group to group the models together, then select edit->align to reference (or something like that, I'm not in front of my computer), which makes the parts print from the same reference, to look like they did in TinkerCAD.

This should create a two-process print that will combine the two pieces just as you want. At least, I think that it will.

Have fun,
DLC

TheBum
Posts: 50
Joined: Fri May 18, 2018 10:13 pm

Re: Impossible slice?

Mon Jun 11, 2018 12:46 pm

DLC's solution is good, but doesn't address the side view of the infill in the top portion of the cutaway cube. Infill relies on the perimeter lines for its strength, so trying to do it without a perimeter line would be problematic. Even if it would theoretically work, you would need to be able to exclude a specific part of the perimeter from skinning and I don't think there's a way to do that in S3D.

RoboDLC
Posts: 49
Joined: Sun Apr 23, 2017 1:30 am

Re: Impossible slice?

Mon Jun 11, 2018 4:12 pm

TheBum wrote:
Mon Jun 11, 2018 12:46 pm
DLC's solution is good, but doesn't address the side view of the infill in the top portion of the cutaway cube. Infill relies on the perimeter lines for its strength, so trying to do it without a perimeter line would be problematic. Even if it would theoretically work, you would need to be able to exclude a specific part of the perimeter from skinning and I don't think there's a way to do that in S3D.
You have your perimeter, you just don't have your top layer(s), on the bottom portion. What I see in the illustration is an exposed infill on the bottom part and full tops and perimeters on all sides on the top portion. Don't MAKE me go and do this to prove it! :)

DLC

ururk
Posts: 25
Joined: Thu Apr 16, 2015 10:21 pm

Re: Impossible slice?

Mon Jun 11, 2018 4:20 pm

I’m going to try a few things tonight - I realize trying to print infill without a perimeter will be a disaster, so at a certain point this will just be an academic excercise. DLC’s suggestion gave me an idea...

TheBum
Posts: 50
Joined: Fri May 18, 2018 10:13 pm

Re: Impossible slice?

Mon Jun 11, 2018 4:40 pm

RoboDLC wrote:
Mon Jun 11, 2018 4:12 pm
What I see in the illustration is an exposed infill on the bottom part and full tops and perimeters on all sides on the top portion.
Based on another of the OP's posts, the illustration isn't a true representation of what he's attempting to get to. He basically wants to see a cross-section of the infill where the corner is cut out, without the perimeter face.

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