imagine two neighbourgs triangles sharing same side

tri 1 being abc, and tri 2 being bcd

Say in your editor you need to subdivide tri2 in 2
now you have 3 triangles, first is same, but triangle 2 and 3 have a shared 
vertex between b and c of the first triangle
this is no longer continuous. Now depending on angle, tri 2 and 3 will generate 
possible conflict with tri 1.

To respect the rule, keeping this split example, tri 2 should not split along 
side tri 1 and still share b&c.

Fabrice


On Dec 23, 2009, at 4:03 AM, Stephen Hopkins wrote:

> hmm. Can't really visualize what you are saying. Is there anywhere I
> can see examples of how a triangle is broken by a vertex? I could
> upload my modelviewer swf if you guys want to see the thing i'm trying
> to fix. Lets you see wireframe/shaded. I will upload it when my ftp
> server goes back up. Thanks for all the help so far.
> 
> On Dec 22, 3:21 pm, Fabrice3D <[email protected]> wrote:
>> yes these are true, but not continuous
>> 
>>> * If you want to place one model on top of another, it's good
>>> practice to cut out the overlaid portion that is not visible. For
>>> example, if you place a house on top of a landscape, you could cut out
>>> the rectangle at the bottom of the house.
>> 
>> the house should be like if part of the floor, then isolated. The walls 
>> vertexes of the house should fit the floor ones.
>> 
>> also other tips regarding sorting issues a bit less common.
>> try to work in size ranges of 1000/10000 to avoid roundings.
>> (That's why Prefab warns you when you load a model that is too small.)
>> 
>> Use the Grid class, and apply the grid to your model position and 
>> objectspace vertices.
>> (I hope add this one to Prefab soon). But in meanwhile its in geom package.
>> 
>> here a working filehttp://www.closier.nl/playground/grid.swf
>> what you see here is a non aligned series of meshes on which you can apply a 
>> grid to the vertices.
>> of course, its a good idea to apply weld and render after its been modified. 
>> The resulting fx is depending on grid size, model size etc
>> That's why in this demo some settings completly ruin the model.
>> But If well applied it also contribute to solve some sorting issues.
>> 
>> Fabrice
>> 
>> On Dec 22, 2009, at 11:17 PM, Stephen Hopkins wrote:
>> 
>>> I think My model is continuous(one piece with extrusions), has no
>>> intersecting faces. I would think that everyone would model like that
>>> for a game or this kind of engine.
>> 
>>> I found these 
>>> tipshttp://worldfoundry.org/bin/view/WorldFoundry/DocumentationZSort
>> 
>>> I'm guessing that the artifacts are there because my triangles aren't
>>> all about the same size. Does the basic renderer use average-z-sorting
>>> of each 3 vertices of a triangle?
>> 
>>> HOW TO BUILD YOUR MODELS TO MINIMISE Z-SORTING ARTEFACTS
>> 
>>>    * Use convex models where possible (avoid concave models).
>> 
>>>    * Avoid overlapping faces and intersecting polygons.
>> 
>>>    * If you want to place one model on top of another, it's good
>>> practice to cut out the overlaid portion that is not visible. For
>>> example, if you place a house on top of a landscape, you could cut out
>>> the rectangle at the bottom of the house.
>> 
>>>    * Avoid triangles that span the extent of the model. For example,
>>> artefacts occur when you have extremes in the size of triangles that
>>> are next to each other ( a long thin triangles surrounded by smaller
>>> ones).
>> 
>>>    * Manipulate the sort keys for the primitives and the order
>>> tables.
>> 
>>>    * Generally, the bigger the size of the order tables the better.
>> 
>>>    * Be aware of overflow of primitives, keeping in mind the extra
>>> primitives accumulated by clipping.
>> 
>>> On Dec 22, 1:51 pm, Peter Kapelyan <[email protected]> wrote:
>>>> Make sure no polygons intersect others, and vertices are shared among 
>>>> faces.
>> 
>>>> These are two major things to keep in mind to not only optimize models but
>>>> also keep them clean looking for
>>>> away3d.
>> 
>>>> -Pete
>> 
>>>> On Tue, Dec 22, 2009 at 4:44 PM, Stephen Hopkins 
>>>> <[email protected]>wrote:
>> 
>>>>> oh ok cool. well back to the other question. Not sure what you mean by
>>>>> continuous modeling. Does this have to do with edge flow? Never heard
>>>>> of it before, didn't find it on google.
>> 
>>>>> On Dec 22, 5:17 am, Rob Bateman <[email protected]> wrote:
>>>>>> Hey Stephen
>> 
>>>>>> short answer - yes! But as with all things in lite, the implementation
>>>>>> will be a stripped down, simplified version
>> 
>>>>>> cheers
>> 
>>>>>> Rob
>> 
>>>>>> On Tuesday, December 22, 2009, Stephen Hopkins <[email protected]>
>>>>> wrote:
>>>>>>> Are there plans to add lights, shaders and filters(mainly fog filter)
>>>>>>> to the away3dlite?I am currently using away3d but would like to
>>>>>>> migrate to away3dlite if it is faster.
>> 
>>>>>> --
>>>>>> Rob Bateman
>>>>>> Flash Development & Consultancy
>> 
>>>>>> [email protected]
>> 
>>>> --
>>>> ___________________
>> 
>>>> Actionscript 3.0 Flash 3D Graphics Engine
>> 
>>>> HTTP://AWAY3D.COM

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