Bug Internal Supports missing first layer

[FrankSchwab 0]

I'm having a problem.  Internal supports seem to be missing the initial layer.  I had this problem in Cura 4.8, and just installed 4.10.0 hoping it would resolve the problem, and it still exists.  Using Cura defaults for all options except "Generate Support" is checked, on the "Generic PETG" "Draft - 0.2mm" profile. 

 

For example, attached is an OpenSCAD sourceSupportTest.zip file and .stl for a simple hollow cylinder with a single-layer bottom.  When I preview and review layers:

1. Layer 1 covers the entire bottom of the cylinder, as expected.

2. Layer 2 (attached) starts building the walls, as expected.  But the support structures aren't getting built which isn't as expected.

3. Layer 3 (attached) continues building the walls, as expected, and starts building the support structures.

 

I've tried making the initial layer all kinds of different thicknesses, as well as selecting different profiles (0.1, 0.15, 0.2, 0.3), and the problem persists.  Eliminating the single-layer bottom eliminates the problem; the support structures start getting built on Layer 1 as expected. 

 

I'd appreciate any help that anyone might have.

 

Edited August 31, 2021 by FrankSchwab
Added comment about removing layer 1

[Torgeir 263]

Hi @FrankSchwab

 

Welcome in here.

 

I downloaded your file and looked at it using Cura 4.10.0.

 

It came up just fine for me, -cannot see any problem - here's a picture in preview mode.

 

 

Here you see the support for the top of the closed cylinder (yellow climbing "zig-zag" pattern), the blue infill in between the wall -and there is also a tiny support in between the top layers.

 

I'm using only skirt found under "Build Plate Adhesion".

 

Maybe I'm missing something here?

 

 

Thanks

Torgeir

 

 

 

 

 

Edited September 1, 2021 by Torgeir
Text error.

[obewan 37]

Setting the 'support Z distance' too 0 will start the support on layer 2 instead of layer 3.

 

[FrankSchwab 0]

16 hours ago, Torgeir said:

Hi @FrankSchwab

 

Maybe I'm missing something here?

 

 

Thanks

Torgeir

 

 

 

 

 

 

Thanks for looking, Torgeir.

Your image is on layer 16 or 18.  Can you look at layer 2  and layer 3 (or 3 and 4, depending on the layer thickness you use) instead? 

 

 

Edited September 2, 2021 by FrankSchwab

[FrankSchwab 0]

15 hours ago, obewan said:

Setting the 'support Z distance' too 0 will start the support on layer 2 instead of layer 3.

 

 

Ding, Ding, Ding, I think we have a winner!  This isn't a "bug", it's a "feature".  After finding the setting and reviewing the docs, I understand now, and this is intentional behavior to allow supports to be easily removed on the bottom side as well as the top side of the support. 

 

Sigh.  10 million options.  Some day I'll learn half of them.

 

Thanks, obewan.

[Torgeir 263]

Ok., thanks for the feedback.

 

Torgeir