Advanced Polynomial Modelling

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10-11-2012 03:37 PM
JoanneO_Brien
Occasional Contributor
So I've had a bit of a play with this lovely new function, which by the way is pretty fantastic and just what I was looking for! But I have a question, I keep on getting completely random shapes because when I think I'm drawing a flat plane polygon as a building footprint, often I find it's actually at some other angle so that when I pull it up it does not come up perpendicular to the ground surface. Is there a way to ensure it is being drawn on the ground surface so that the building will be extruded straight up correctly? (not that the other shapes I manage to create don't look very cool, they're just not what I need though! :) )

Hope that makes sense anyway!

Thanks

Joanne
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9 Replies
ScottFujikawa
New Contributor III
Hi. I am experiencing a similar concern. When I use the Polygon Shape Creation tool on what I believed was the ground surface of my combined imagery+rasterized height map, I find that the shape is drawn below surface and at an angle not consistent with the apparent imagery surface. I'm also having issues with exporting photo-textured meshes that I have successfully created in that when viewed on the Web Scene viewer, polygons and textures are missing from those buildings.
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MatthiasBuehler1
Frequent Contributor II
Hi !

Sorry for the late reply.

1]
It seems you have some issue when drawing buildings if a terrain exists. That can indeed give some issues. For now, try modeling in an empty scene..

2]
Just as a reminder:

The Polygonal Modeling Tool creates Shapes which you can texture. A Shape is NOT the same as a final 3D Model. But yes, you can export it as a model, e.g. if you don't assign a valid CGA rule.

3]
WebGL displays objects with 'Backface Culling'. This means that the BACKSIDES of the polygons are not rendered, thus seem to be missing. This is defined by the vertex order ( normals ) of those polygonal faces.

To fix this, you can change the vertex order on those faces which 'look inwards' by using 'reverse Normals' from the Shapes Menu. Double click a shape to select it.

To see which faces are the problem, toggle the light with the 'L' key between scene light and head light and toggle 'Single-Sided Lighting in the viewport's display settings menu (cogwheel menu). The faces which then are rendered black need to be reversed.

Let me know if you find out how this works. Otherwise, I'll help further.


Good luck !

matt
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ScottFujikawa
New Contributor III
Hi Matthias,

Thank you for your very helpful instruction and insight.

Regarding modeling on a terrain (Ans 1), since we plan to import models that are cut to the imported terrain and occasionally use the Polygon Creation Tool to create additional models in that environment, will this concern be addressed in the future?

I tried your suggestion of reversing faces that were not showing in the web scene (ans 3) and that fixed the missing faces concern. The reversing of the rooftop in CE, however, hides the applied roof texture from normal view. I also noticed that both of the building shapes I created had reversed rooftops. (I attached screenshots of my experience). Also when I toggled the 'L' key and the 'Single-Sided Lighting', the rooftops went black as you advised, however, the reversed walls of the shapes did not.

Thank you again for your assistance,
Scott
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JoanneO_Brien
Occasional Contributor
Regarding modeling on a terrain (Ans 1), since we plan to import models that are cut to the imported terrain and occasionally use the Polygon Creation Tool to create additional models in that environment, will this concern be addressed in the future?
Scott


This is my concern also, I noticed the error when I wanted to add a block shape to fill an area for a potential new building and it all went wrong. But In the scene I was using I had not imported any terrain, all I'd done was import some obj files from sketchup, does this cause the same issues as a terrain model would then?
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MatthiasBuehler1
Frequent Contributor II
Hi Joanne and Scott.


Yes, this concern is addressed in future and this is just the first version of the tool .. :)

What would be really insightful for us here is to get precise inputs on how you think the tool should 'behave', based on your 'real world' use cases, so we can build on those inputs. (Sketches, images of target buildings, .. all welcome.)

Existing static models should not have an influence at all. Please send me a series of steps you take to reproduce the problem if it really happens.

* * *

Concerning the 'normal view' of the rooftop polygons, not sure what causes this issue. Did you try flying into the building with the cam and check the inside ?
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JoanneO_Brien
Occasional Contributor
Some thoughts re this tool:
1) The rectangular shape tool is a bit tricky to play with as it keeps on changing which plane it's focusing on, so seems only suited to very basic surfaces. It'd be handy if you could use this tool to click on the first two corners of the plane you want to head in and then drag the shape across the rest to finish the rectangle
               
           eg: In the first screen shot it shows a building that has been created. In this I was trying to draw a rectangle flat against the side of the building but it flickers between planes, so if I was able to click on the first and second corners before pulling it down the side of the building this would make it easier to define the plane, and the double click to finish off the rectangle.

2) The second screenshot shows a classic example of where I've tried to create a basic polynomial shape to fit within some imported collada models from Sketchup. Whe I define the area it gets confused between which plane to use and so the extruded building has a very interesting shape which isn't the desired result! It would be good it there was some way to indicate when it was on the proper base plane when drawing the polygon, eg a coloured line or some way to snap to the base level? This would also be useful when dealing with terrain models. For this it'd be good to define whether to follow the terrain model base or a planer base, prehaps also choosing whether the scope is world.up or not etc..

3) Another thing I've been working on is getting a slope onto my building. Now I have a series of rule files I've created using the facade wizard. Idearly I'd love to be able to assign these files to the different building sides. Now sometimes this works, as shown by the black glass in the third screenshot, but Where the building has the sloped edge it's causing the image to rise in stepwise series which creates a jaggered edge rather than a smooth edge along the slope which is what I'd want.

An alternative to this form of assigning rule files to the individual sides would be assigning one rule file for the whole building with the wizard facade rule files imported into it, but when I tried to do this myself it didn't seem to work. I guess this point/issue is also associated with the thead here : http://forums.arcgis.com/threads/65683-Angled-Buildings

4) I've also noticed that when you use the Polynomial Shape Creation tool it seems to jump around, by this I mean I go to draw up a building footprint and get halfway through and find that the line has jumped to somewhere else on the page leaving me with an incomplete shape. When I go to finish the shape it doesn't seem to finish properly either, so I can't extrude the shape.

5) On this note I drew some shapes on a brand new scene, although I had given the scene a coordinate system, but I thought I was drawing them on a flat planer as there has been no terrain imported etc. Anyway when I tried to extrude them, I got crazy shapes as shown in the 4th screen shot!! Also note for some reason the shapes were created below the wire frame and definately not straight!

6) It would also be nice to have an undo button for the Polynomial Shape Creation tool where if you're drawing the shape and you make a mistake it undo's that mistake and leaves the line still attached waiting for the new line to be redrawn rather than completely detatching from the original shape...

I probably have many more wonderful things to discover and come up with more things for my wishlist but this'll do at the moment.

Regards

Joanne
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MatthiasBuehler1
Frequent Contributor II
Hi Joanne !


Thanks for your inputs ! I have forwarded them to the according people.

Just in short concerning the Facade Wizard:
The Facade Wizard basically only works properly on vertical, rectangular shapes. If the shapes are trapezoid, the shapes will nevertheless be split according to the FW rules, but the resulting shapes remain trapezoid. At specific points in the Facade Wizard code, cubes are inserted for the texturing, this will in the end result in that stairstepping on the borders. Inevidable currently.

Thus, for the non-rectangular shapes, you'll have create some custom code to adapt to this if you need more complex geometries other than just the flat-textured shape itself.


Matt
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JoanneO_Brien
Occasional Contributor
Ah that gives me an idea of a work around, so no problems :)

Just another thought for the polynomial shape creation tool, I use this to split up my building parcels since these have been imported from ArcGIS and often combine buildings of different heights, anyway to do this I use the tool, following the dashed orange line to get the straight line. But unfortunately this dashed line disapears when I reach the opposite edge which I want to connect to so I have to guess the final position, is it possible for this like to always be visible when on a straight line? (check out the screenshot to see what I mean).

Also it'd be awesome it there was a way to make the building parcel either semitransparent or wireframe while maintaining the terrain image below, because often to make these splits I'm using the aerial image displayed below to work out where the buildings change within the pacel.

Regards

Joanne
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MatthiasBuehler1
Frequent Contributor II
Hi !

The system gives you at the moment only what you see, there's no options.

The system uses complex heuristics on what the user might be interested in, but obviously, not all cases are solved properly yet.. Our developer is continuously working on the thing, so chances are great we'll see great improvements (even though most stuff is invisible :) )

Matt
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