differed does not work

[jdawgaz]

The following code on the wiki does not provide the desired result:

differed("hole")
ball(50)
orient([x,y,z])
rod(d=25, h=55, $class="hole");

I am on osx Sierra (10.12.4), openscad (2017.08.03). Latest version on relativity.scad.

[davidson16807]

Have you tried building with F6?

[jdawgaz]

that worked, but doing an F5, it did not. can't remember a time, that F5 preview & F6 view did not look alike. Why is that? and is there a way to fix that?

…

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On Wed, Aug 23, 2017 at 8:54 PM, Carl Davidson ***@***.***> wrote: Have you tried building with F6? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#13 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABZex4469ODxgbi6YL0VleXg5BgLQsq0ks5sbPP6gaJpZM4PA1oZ> .

[davidson16807]

differed() takes the difference between positive and negative spaces. If you don't specify the positive space, it defaults to whatever the children are. So that code takes the hole and subtracts it from the hole plus some other stuff. Subtracting a part by itself can produce this sort of behavior.

The problem goes away if you set the positive space not to include the hole:

differed("hole", "not(hole)")
ball(50)
orient([x,y,z])
rod(d=25, h=55, $class="hole");

So maybe this is an issue with defaults? We could set positive space to be the negation of the negative space, if no default is provided.

[jdawgaz]

I changed to code to this, and it works (and looks as expected).

You could change the wiki to reflect what the code should be, or change the defaults, so that when we put the code (that I first posted, from the wiki), it looks and acts as expected.

thanks.

[aleung]

It's better to change the default positive selector to "not()".