topic Block creation in ArcGIS CityEngine Questions

Block creation

JussiViinikka1 — Tue, 12 Mar 2013 16:54:38 GMT

Hi,

Is it possible to create blocks without graphs? Basically I´d like to draw a polygon that I would then apply a subdivision rulefile on and then apply another rulefile on the divided parts. So the block subdivision rulefile should be able to create shapes. It seems to me that the way blocks (and the subsequent lots) are now created is more or less like this but in a rather implicit way, for example I cant find the block subdivision rule file CityEngine uses anywhere... I suppose its because the actual creation of separate shapes is something cga alone cant handle? If blocks can only be created with delimiting street segments is it possible to delete the streets from one (or two or three) sides of the block? It seems not.

I guess the only way to mimic creation of blocks without streets is to make the width of the streets = 0?

Thanks for clarifying this,
Jussi

Re: Block creation

MatthiasBuehler1 — Wed, 13 Mar 2013 15:16:27 GMT

Hi Jussi,

The Shape Creation process using the 'Dynamic City Layouts' system is independent of CGA. It's just used to produce shapes for later use with CGA. This may be changed one day though.

What you can do though, is to use the menu Shape > Subdivide on a polygonal shape and have it subdivided with the same subdivision parameters. Though this is not dynamic. To go back, use 'undo'.

There's no way to go from a polygon to define a dynamic block with 0 street width unless you code this in Python. So this would be an option. Though I'd not recommend this because usually you have some issues with proper block subdivision with streets of width 0.

Does this help ?

M.

Re: Block creation

JussiViinikka1 — Wed, 13 Mar 2013 16:01:04 GMT

Hello Matthias,

Yes its more or less like I suspected. The Shape -> Subdivide doesn't really work, because if its not dynamic its not very useful in planning/design.

I managed to do what you warned about though, creation of 0 street width blocks (not through making a polygon first and going from that, but directly drawing 0-width streets), and it seems to work nicely. Don't see any problems with the subdivision either, maybe in some circumstances I will. But yeah, it would be cool if the block parameters could be defined in a rule file that would then be applied on any given polygon. That way the rules would be written down and saved somewhere, which is good if the intention is to transmit those rules somehow to official planning documents as well. Probably theres a bunch of technical hurdles, but I don´t see why it couldn't be in the CGA itself. Probably it would find other use cases as well, and then you wouldn't need parallel systems like Dynamic City Layouts. Or am I missing something?

Thanks for your answer!
-Jussi

Re: Block creation

MatthiasBuehler1 — Wed, 13 Mar 2013 16:25:54 GMT

Hi

Improving these workflows is planned. Going from parametric subdivision to procedural subdivision indeed would not be too complicated, but there's things involved that need be solved.

We've thought of going that route ..

We'll see .. 🙂

Matt