[Bf-committers] Mirror and array modifiers for curves

[Sergey I. Sharybin]

Am i right, that curves stores theris data in DispList structures and 
one DispList structure contains information about vertices from one 
connected component?

If so, we could affect on this DispList-s and create new one in 
constructive modifiers. It will work perfect for curves (and maybe the 
same approach will work fine for surfaces - I've not looked at them 
yet), but handling of such things as bevel-ing, taper-ing and text on 
curve-ing will be quite difficult. This objects should be also modified 
for each constructed set of DisplList separatelly (i mean we can't use 
this objects for whole original and contructed DispList-s). Maybe this 
small example will illustrate what i mean: Curve consists of 
dl_1,dl_2..dl_n displists and has got obj as bevel object. After 
applying mirror modifier curve will consists of dl_1..dl_n, 
dl_n+1..dl_2*n displists and we should use obj as bevel object for first 
n displissts and mirrored obj for the last n displists,

Brecht Van Lommel wrote:
> Hi,
>
> On Tue, Feb 16, 2010 at 1:21 PM, Sergey I. Sharybin<g.ulairi at gmail.com>  wrote:
>    
>> Am I right that in this case we should have absolutely new constructite
>> modifiers for curves (i mean existing handlers will be useless for curves)?
>> Maybe it would be better to have some common interface for modifying
>> curves, meshes, surfaces?
>>      
> Curves and surfaces indeed can't just be modified like meshes, they
> have certain constraints that need to be respected and weights that
> need to be preserved. It would be possible to code some sort of
> abstraction but I think that would lead to hard to understand code. In
> my opinion these should be implemented separately as you'd need to
> have many exceptions in the code anyway. Though for example an array
> modifier could of course share code to compute the transformations.
>
> Alternatively you could run constructive modifiers on the tessellated
> result, that's not ideal though.
>
>    
>> Does render engine convert curves/surfaces to meshes before rendering?
>>      
> They are tessellated but not converted to a Mesh or DerivedMesh, but
> functions exist to do this for the Convert operator.
>
> Brecht.
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-- 
With best regards, Sergey I. Sharybin