Voids in GDL

[Ingolf]

I want to make a Block in GDL with an internal hole, the object made in the simplest possible way. Of course I can make four walls and a roof and make a Block with a hole that way, but I want to make two Blocks, one regular and one smaller void-Block. Is there a command for void in GDL?

[runxel]

Yes, that's possible. You should look in to the SUBGROUP command.

[Ingolf]

Thanks for a swift answer. I suspected the Subgroup. But how to script a Block and a void with Subgroup?

[DGSketcher]

Here's a couple of links you might like to explore...

https://gdl.graphisoft.com/gdl-basics/advanced-3d-components

https://gdl.graphisoft.com/reference-guide/solid-geometry-commands

[Barry Kelly]

BLOCK and BRICK can not have a hole directly scripted in them.

You can use GROUPs as others have suggested and SUBGROUP one from the other.

Not hard, but you need to know how the grouping works.

I would just use the PRISM_ command (or its variations.

PRISM_ 10, 1.0,

0.0, 0.0, 15,

1.0, 0.0, 15,

1.0, 1.0, 15,

0.0, 1.0, 15,

0.0, 0.0, -1,

0.2, 0.2, 15,

0.8, 0.2, 15,

0.8, 0.8, 15,

0.2, 0.8, 15,

0.2, 0.2, -1

The -1 mask means the following nodes will cut a hole.

Barry.

[Ingolf]

Thank you Barry. But: I need a script where the hole does not cut all the way through the cube. That will probably not be possible in your otherwise elegant solution?

[Barry Kelly · Accepted solution]

Ah, you want a hollow block with 6 sides still?

You could add slabs (prisms) to the top and bottom to plug the hole.

But easy with GROUPs.

GROUP "box"

BLOCK 1, 1, 1

ENDGROUP


GROUP "void"

ADD 0.2, 0.2, 0.2

BLOCK 0.6, 0.6, 0.6

DEL 1

ENDGROUP


result = SUBGROUP ("box","void")


PLACEGROUP result

This is the wire frame view.

Barry.

[Ingolf]

Hello DGSketcher

The link https://gdl.graphisoft.com/gdl-basics/advanced-3d-components will probably help me on track. Thank you 🙂

[Ingolf]

That worked well, and not a too complex formula. I changed it so I could see the void from the botom 🙂

Material 4

GROUP "box"

BLOCK 1, 1, 1

ENDGROUP

GROUP "void"

ADD 0.2, 0.2, 0

BLOCK 0.6, 0.6, 0.6

DEL 1

ENDGROUP

result = SUBGROUP ("box","void")

PLACEGROUP result

How did you do the list (with the GDL-script) in your answer? How did you place the list in a grey box with a slider? 🤔

[Barry Kelly]

Expand the editing tool bar (3 dots) at the top where you type your reply.

That will create the code box.

Barry.