topic Re: Trim a Flat Top in ArcGIS CityEngine Questions

Trim a Flat Top

BurakAydin1 — Mon, 07 Oct 2019 14:38:12 GMT

Hi,

I have the following problem:

since i have a hilly terrain, i extrude the buildings with the command "extrude(world.up.flatTop,0)". However, the flat tops are much too high in some places (see "flatTop").

Is there a way to trim these flat tops? Preferably so that the door is always on the floor, or a flat top is created from the door onwards. Matthias Buehler‌ Cheryl Lau‌ Geoff Taylor‌David Wasserman‌Chris Wilkins‌Thomas Fuchs‌Michelle Mathias‌L R‌Martin Manzer‌ Elliot Hartley‌Dan Patterson‌

Re: Trim a Flat Top

DavidWasserman — Mon, 07 Oct 2019 16:51:46 GMT

To some extent given the degree of the slope, it is not clear if the problem is the need to reduce the height or just to add stairs.

Another option is to potentially identify the best place to put the door based on the sampled ground elevation of each side shape, but I am not sure elevation sampling is that exact.

I am curious if the resetGeometry and scope.elevation functions/elements would help here, but I have not gotten to test them that deeply.

Re: Trim a Flat Top

BurakAydin1 — Mon, 07 Oct 2019 18:16:38 GMT

Hi David,

creating stairs would be an option, but how do you create the stair rule for it?

That would be the best solution, but i don't know how to identify the best place for the door.

Are resetGeometry and slope.elevation commands? I haven't found anything in the cityengine help.

Re: Trim a Flat Top

Anonymous User — Mon, 07 Oct 2019 20:53:23 GMT

re: new commands: resetGeometry is new as of 2019.0. scope.elevation is old. I assume accuracy of scope.elevation is based on resolution of Esri's elevation service in the part of the world you are at.

Re: Trim a Flat Top

Anonymous User — Mon, 07 Oct 2019 23:15:06 GMT

Here's an example of a way I've dealt with hills and foundations in the past. Not addressing stairs tonight, maybe tomorrow. CGA rule is attached.

Re: Trim a Flat Top

BurakAydin1 — Tue, 08 Oct 2019 16:46:03 GMT

Hi Chris,

in fact your CGA Rule has brought me a lot, thank you!

But the buildings in some places are still too high, so a staircase would be helpful.

Do you also have a CGA Rule for the stairs, that would be great

Re: Trim a Flat Top

Anonymous User — Tue, 08 Oct 2019 18:47:51 GMT

I have other stair rules for specific cases, but I just made a simple version here (meaning very few options). It uses the Foundation example from yesterday. It rotates the door down to make the stairs using an imported stair rule. You have to adjust the height manually - finding a solution to that is out of my time frame. Also, I added a doorIndex attribute to tell it which wall gets the door (uses split.index).

Rules attached here.

Re: Trim a Flat Top

BurakAydin1 — Thu, 10 Oct 2019 18:24:52 GMT

Hi Chris,

your rules are great. Now everything looks much better (see "stairs").

But some of the heights are not right, as you already mentioned (see "stairs1").

I'll probably solve it with s().

Nevertheless you helped me a lot, thank you very much

Re: Trim a Flat Top

DavidWasserman — Tue, 15 Oct 2019 16:27:37 GMT

Thanks for taking a look at this Chris!