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dynamically displaying buildings

AlexandruVasile

Hi,

I am working on an entire city (lots of buildings, streets, DEM, parks etc.) with quite a bit of detail.

So obviously my computer starts failing when I apply the rules to more than a few 'Lots'.

Getting more RAM is not really a solution (considering the size of the city).

So I was wondering if there is a way of dynamically displaying the objects.

At the moment I have defined 2 LODs in my rule. It would be perfect if the LOD

would dynamically change depending on the zoom (how close to the building)

and also on the perspective (which buildings I see right now).

So I only give detail to what I see and when I am close to it.

Thanks.

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AlexandruVasile

So I tried to lead my scene to Unity.

I tried the script from here:

http://3decide.com/break-a-leg/ce-to-unity-tutorial

but it didn't work (just kept searching for the terrain). So I just exported my scene as .fbx.Than uploaded it to Unity.

The problem is that it only exports the models which have already been generated. So I have to generate them before I export it to Unity, which kind of defeats the purpose.

So I thought of importing .fbx in batches into a Unity project. The issue here is that the spatial reference is lost; the houses imported the second time ended up in the air somewhere.

I am simply documenting my experiences as I go along. So if someone has any suggestions I am all ears

MatthiasBuehler

Hi,

First of all, to export models, you don't need to generate them.

e.g. just select a shape and go to the exporter. The model does not need to exist in the viewport. CityEngine regenerates the model anyway new in the background for export. You're rather clogging export resources resources when having all displayed. For exports of big datasets, set Java memory (ini file) to about 50% system memory and run ONLY CityEngine. Close all other apps that may interfere with the process. After export, set the value back to something reasonble. [Or just leave CE closed.]

Then it depends on the target application. I also wanted to write about dealing with this instead e.g. in Unity as an example in my last post, but left it out.

I sadly never had time to solve this myself, but game engines provide solutions or plugins for this that just dynamically load models based on the player proximity to a specific model. e.g. if a model's bounding box is visible, load the model.. As said, I don't know the details.

This then leads to the question of file granularity, where I'd say it's best to export 1 file per shape, which then can be loaded by the target app, e.g. Unity. I also assume that you may need to export at least 2 files for each shape: 1 with just the bounding box to check, which files should be loaded, and then 1 file for each LOD that gets triggered again based on proximity.

I'd be really interested in seeing a solution for this. We can collaborate on this, if you like. 😉

About 2 years ago, I searched a bit and found a plugin ( never tested it ) that does 'asset streaming' (harddrive or cloud), which would be exactly what you need.

Cheers !

Matthias Buehler

Head of 3D Technologies

twitter: @MattB3D

-------------------------------

Garsdale Design Limited

matthias.buehler@garsdaledesign.co.uk

www.garsdaledesign.co.uk

AlexandruVasile

Thank you all for the help.

I'll come back when I have something to show.

Regarding the fact that CE is not a visualisation environment: I agree; but what do you recommend I use to visualize my huge modelled city; and also, how should I do that? For example if I want to load it to Unity, I still have to generate the whole city in CE in the first place in order to export it, right? Which, as I said, is too big and my computer can't handle it.

Looking forward to your answers, maybe I won't need to write python after all:)

MatthiasBuehler

Hey Alexandru,

The above inputs should help you code it.

Note:

You'll also need to write some sort of timer that runs all the time unless you want to trigger the update manually each time. Which may slow down the whole thing quite a bit, if you're constantly rebuilding all models.

In general, especially when coding, I never display all models at the same time. But it depends on a use case. Remember, CityEngine is a modeling tool and not a visualization environment..

Regarding visualizing the whole Paris model fully generated: That does not really generate many polygons (in the default state, there, only a few buildings have the high LOD set), thus a good graphics card can display it quite easily. And the fluidity of the viewport is independent of the system RAM. If you have lots of textures, VRAM may have a bit of an impact, but mostly, it's the amount of polygons and especially shadows/ambient occlusion.

Ok ?

Matthias Buehler

Head of 3D Technologies

twitter: @MattB3D

-----------------------------------

Garsdale Design Limited

matthias.buehler@garsdaledesign.co.uk

www.garsdaledesign.co.uk

DavidWasserman

Hi Alex,

I work with Chris.
In terms of CE python specific resources here is a good link.

http://cehelp.esri.com/help/index.jsp?topic=/com.procedural.cityengine.help/html/manual/python/toc.html

While this is in the table of contents, functions related to camera angles/location/and other attributes are found here:
http://cehelp.esri.com/help/topic/com.procedural.cityengine.help/html/manual/python/jscripting/jscripting.View3D.html#View3D-addBookmark

The python section on attributes is here:
http://cehelp.esri.com/help/topic/com.procedural.cityengine.help/html/manual/python/jscripting/jscripting.CE.html#CE-setAttribute

From the look of it you will want setAttribute or some of other python attribute setting.

I hope some of this is helpful.

David

AlexandruVasile

That sounds great, I have only started playing with CE for a few weeks but

I'm sure I will continue to run into issues that this thread will help with.

As a side note: is there a place where we can post .cga files and entire

projects? When I started I could not find such a place,

and it would have been very useful (it's much easier to modify something

than to start from scratch). And now I can post some of my work.

2014-11-05 17:36 GMT+02:00 Chris Wilkins <geonet@esri.com>:

GeoNet
<http://jiveon.jivesoftware.com/wf/click?upn=Dg1s4x8le7Lmxv8KWGaqo8h7SGfRSMkw-2FpvHGF9-2FW3rK-2Bvs1kL9-2FnG6jjf2NZhrLDz0M-2BrY-2By9IaziQEKVk3Hg-3D-3D_0v1izXFVJ-2BmIe51G2FoDc6-2F1uya0mH9hC-2B0fRdlyLgDKhsO7u2iLj4oaBWtf-2BLBiR44WoZYesR58Gnm4ywpY4Ic2DWk-2FauHcHJwsKpW72S-2BBN3o6YgATslNa-2F5HF6nYgDqqZhNzkwAkZBn54qZGK-2Fo0SYpVbMe1MkjV9HA-2FIyiRyaGhs9dnE-2BdC5DCfAqTFHuMTuquBLx9JrahBJUM-2FSByAlMjGEI17fE4q9FebvPlPJAm9oPnRjTjMYSZ-2BC2sZcPk4dkN3WdDJ2ZCUaUcvJhds4kTX-2FGNJOInOEnyVZp4-2BcjSrpIwF0SBtrnCLt9Spy> dynamically
displaying buildings
reply from Chris Wilkins
<http://jiveon.jivesoftware.com/wf/click?upn=Dg1s4x8le7Lmxv8KWGaqo7A4BXwO9PY1WvQ5cXCtK49fe2ljzSLeiFBFjIbQtL-2BIes9B8qlE9pl-2BYyB6LQLcR2YwgZltK7MqmM6Bn5Yyguo-3D_0v1izXFVJ-2BmIe51G2FoDc6-2F1uya0mH9hC-2B0fRdlyLgDKhsO7u2iLj4oaBWtf-2BLBiR44WoZYesR58Gnm4ywpY4Ic2DWk-2FauHcHJwsKpW72S-2BBN3o6YgATslNa-2F5HF6nYg3nVWmj1RKR9NI6fAuYwCdPNP2BisjLswd-2FdWcr92O6Iv2r1yvaBprSlIDiURsGJT9Klh8wJ9m-2FoyA-2FD7bvmzyRJxNmADOw-2FyFL-2BCLy-2FzeYHXm1xvXxFYxHg251MDOsIizJvyqassDkh-2Bp00VVMv4B54y0IB1nx3IsVGPt9jrM-2FZnnOEPayoOfZVL-2BF0ehVX0>
in CityEngine - View the full discussion
<http://jiveon.jivesoftware.com/wf/click?upn=Dg1s4x8le7Lmxv8KWGaqo0VQjeJBYpG9HGC8QZBT-2FExTRYLJbXcf-2FMmthBTqV9I52ol36uESin5Iai9NUpg6inplzzJPZbvZFBuAcGuflgI-3D_0v1izXFVJ-2BmIe51G2FoDc6-2F1uya0mH9hC-2B0fRdlyLgDKhsO7u2iLj4oaBWtf-2BLBiR44WoZYesR58Gnm4ywpY4Ic2DWk-2FauHcHJwsKpW72S-2BBN3o6YgATslNa-2F5HF6nYgUdHmyLK88C5Ty1ZePxrFhBruocMJncivzVD-2B5hPDfvE04Jq7V3L-2Fz3jZ75J4KQnR1ZlsOV5cjIU-2BX3IsDEQtpGQanSoOHNifZSXxsRroRViePi7mYHnTckulhmVfzPSXcxOjvRsQAfVlzS1TNpeIqPEX1b40LRUAcGnABk-2FaPrW-2F97ps6h7fGB2JJn1GE5K8>

AlexandruVasile

Thanks Chris,

I really appreciate it

Anonymous User

We should start a new thread concerning performance. There are a lot of issues that affect it, thought. I'll start accumulating some knowledge about this.

Anonymous User

I'll find a script with some of the right stuff in it, but will be later in the day.

AlexandruVasile

Yes, python is an option for me. I have not worked too much with it and certainly not in CE, but I can learn:)

Could you please point me to some resources. I have no idea where to start:

like where to get the location and direction of the current camera, where can I look, etc.

Thanks for the help.

Alex

ialixandroae

Hi ,

What if RAM is a solution to this problem?...

I saw a presentation where Paris was generated in CityEngine and the movement was without lag. What specification do you think would be enough for rendering and generating an entire city without this kind of problems?

Thanks !

Anonymous User

This is not a built in feature, so one possible solution is to use python. Pseudo-code:

1. Get location and direction of the current camera.

2. From that, determine which objects fall in viewshed.

3. Set an object attribute on each object falling in the viewshed, telling which LOD to use.

4. Regenerate all items in the viewshed.

Only issue is #2, since I can't say off top of my head how to find if object is in the view or not. So if we can't figure that out, then you can easily determine all objects that fall in a radius from the camera, but then you have items behind the camera that would be at an unnecessarily high LOD.

Is python an option for you?

Chris

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