[Bf-committers] In need for help/documentation for modifiers

[Tobias Oelgarte]

At least this is some starting point. A simple documentation on this 
could be really handy. I will try to setup a basic modifier and see if i 
run in any trouble. If so, i will ask back, since this could also be 
helpfull, if you decide to write a documentation on this. For now i will 
spend my time to read more into the code.

Thank you. Without this i might have searched for hours/days and 
probably given up frustrated.

Jeroen Bakker schrieb:
> Hi,
>
> I have a small step by step mind dump, but have not yet had time to 
> write the complete documentation about it. see below. there is also a 
> developer website who mentions it, but cannot find it right now.
>
> Add custom modifier
> 1. DNA_modifier_types.h --> add ModifierType enumeration (must start 
> with eModifierType_[NAME])
> 2. DNA_modifier_types.h --> Add [NAME]ModifierData struct. first field 
> must be ModifierData modifier
> 3. rna_modifier.c -->     {eModifierType_[NAME], "[NAME]", 
> ICON_MOD_PHYSICS, "Surface", ""},
>
> static void rna_def_modifier_test(BlenderRNA *brna)
> {
>      StructRNA *srna;
>
>      srna= RNA_def_struct(brna, "TestModifier", "Modifier");
>      RNA_def_struct_ui_text(srna, "Test Modifier", "just a test");
>      RNA_def_struct_sdna(srna, "TestModifierData");
>      RNA_def_struct_ui_icon(srna, ICON_MOD_PARTICLES);
> }
> add sdna fields
> static StructRNA* rna_Modifier_refine(struct PointerRNA *ptr)
>   add case
>
> call method from register
>
> 4 modifier.c
>          mti = INIT_TYPE(Test);
>          mti->type = eModifierTypeType_Constructive;
>          mti->flags = eModifierTypeFlag_AcceptsMesh;
>          mti->initData = testModifier_initData; // method to be called 
> when created
>          mti->copyData = testModifier_copyData; // method to be called 
> when copied
>          mti->applyModifier = testModifier_applyModifier; // method to 
> be called when applied
>          mti->applyModifierEM = testModifier_applyModifierEM; // method 
> to be called when applied
> /** test modifier **/
> static void testModifier_initData(ModifierData *md)
> {
> }
>
> static void testModifier_copyData(ModifierData *md, ModifierData *target)
> {
> }
> static DerivedMesh *testModifier_applyModifier(ModifierData *md,
>                             Object *ob,
>                             DerivedMesh *dm,
>                             int useRenderParams,
>                             int isFinalCalc)
> {
>      return dm;
> }
> static DerivedMesh *testModifier_applyModifierEM(ModifierData *md,
>                               Object *ob,
>                               EditMesh *editData,
>                               DerivedMesh *derivedData)
> {
>      return testModifier_applyModifier(md, ob, derivedData, 0, 1);
> }
>
> 5. add user interface panel.
> properties_data_modifier.py
> class DATA_PT_modifiers add method [NAME]
>
> 6. implement modifier.
>
>
>
>
> On 10/08/2010 12:30 PM, Tobias Oelgarte wrote:
>   
>> Hello,
>>
>> Im currently looking into the sources of blender and try to understand
>> how the modifiers are working. Writing a modifier seams to be simple,
>> but on the other side there are many other files that are keeping lists
>> of them (to know which are available). This is somehow like finding all
>> needles in a haystack.
>>
>> Is there a documentation on modifiers, that lists all the files that
>> need to be changed if you write/add your own modifier? Need this files
>> to be changed, or will they be updated automatically? (guess not)
>>
>> Somehow i miss some document that points out how i can write my own
>> modifier from scratch (including gui etc.). At least a very simple
>> example would be nice.
>>
>> Currently i developed code to write a so called RestoreVolume-Modifer,
>> that ensures that a closed mesh keeps/restores it's original volume
>> after deformations (due to other modifiers). Simplest example would be a
>> muscle that contracts and will grow on the sides (controllable by vertex
>> group), because of the loss of volume in length.
>>
>> Any suggestions or hints?
>>
>> Best wishes Tobias Oelgarte
>> _______________________________________________
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>> Bf-committers at blender.org
>> http://lists.blender.org/mailman/listinfo/bf-committers
>>
>>    
>>     
>
>
>