Hey Nicolas,
This depends of the frequency of your scenegraph traversal. For sure, if
you run it like this
Start: sphere with bend modifier, Material2 assigned (226)
traversal
Assign material 1 (206)
Change the bend angle 10 times (226)
traversal
the system will break. But visiting at this frequency will work:
Start: sphere with bend modifier, Material2 assigned (226)
traversal
Assign material 1 (206)
traversal
Change the bend angle 10 times (226)
traversal
Since you can avoid visiting entire branches because of the hierarchical
attribute. I bet a traversal would be really fast to do reducing the number
of visited node (all nodes are not traversed unlike the original visitor
pattern).
The frequency is up to you, with a custom timer, or by subscribing to
"siOnValueChanged" should be enough.
-jo
2012/5/4 Nicolas Burtnyk <nico...@redshift3d.com>
> Unfortunately I was able to pretty easily break this system :(
> While playing around with all kinds of edits, I noticed that when I had
> Material1 assigned to my object the hierarchical eval id was 20 less than
> when I had Material2 assigned. I also noticed that if the object had a
> bend modifier on it, changing the bend angle would increment the
> hierarchical eval id by 2. So with this sequence of events, I got the same
> eval id before and after edits.
>
> *Hierarchical eval id of the sphere is shown in brackets at each step*
> Start: sphere with bend modifier, Material2 assigned (226)
> Assign material 1 (206)
> Change the bend angle 10 times (226)
>
> The problem is the way the hierarchical eval id is computed by simply
> summing the eval ids up the hierarchy. Maybe instead, I could crawl the
> hierarchy myself (annoying but not a big deal) and compute a hash from all
> eval ids in the hierarchy of the object. Assuming a suitable hash
> function, any change to any eval id in the hierarchy would cause big
> changes in the hash and bring the probability of a false negative down to
> some infinitesimally small amount.
>
>
> On Fri, May 4, 2012 at 6:12 PM, Nicolas Burtnyk <nico...@redshift3d.com>wrote:
>
>> To Steven : if the application of the shader to the object creates a
>> shader and a material and connects the shader to the material, then yeah,
>> those events are called. But if you assign an existing material, they're
>> not.
>>
>> To Jo: I'm playing with this right now and it's very promising. I wonder
>> though if it's possible to get the same hierarchical evaluation id after
>> some edits. The reason I'm worried about this is that I noticed that
>> assigning different materials to an object caused the hierarchical
>> evaluation id to go up and down. I wonder if some combination of edits
>> could result in the same evaluation id and therefore cause my system to
>> think nothing has changed which would obviously be pretty bad! Other than
>> this worry, and verifying that this is valid for all kinds of edits that
>> might change the way an object is rendered, this technique of checking the
>> hierarchical object id might be a lot simpler than chasing down every last
>> little command, callback, etc.. that can change the scene.
>>
>> Thanks guys!!
>>
>>
>> On Fri, May 4, 2012 at 6:02 PM, Steven Caron <car...@gmail.com> wrote:
>>
>>> in my quick test i applied multiple shader's from the menu, both
>>> standard and custom. both seemed to get fired. i could have been wrong.
>>>
>>>
>>> On Fri, May 4, 2012 at 5:20 PM, Nicolas Burtnyk
>>> <nico...@redshift3d.com>wrote:
>>>
>>>> Thanks Steven!
>>>>
>>>> I already use siOnConnectShader (and siOnDisconnectShader) to track
>>>> changes to the shader tree. These don't get fired as a result of assigning
>>>> a material to an object. siOnCreateShader only gets called when you create
>>>> a shader node and in fact partially fails at even that since it doesn't get
>>>> called when you create a material (which creates a shader as well).
>>>>
>>>> Thanks for the tip on material assignment via drag & drop. Kind of a
>>>> shame that it ends up calling CopyPaste command but it should be simple
>>>> enough to monitor for that command as well.
>>>>
>>>> -Nicolas
>>>>
>>>>
>>>>
>>>> On Fri, May 4, 2012 at 4:54 PM, Steven Caron <car...@gmail.com> wrote:
>>>>
>>>>> have you tried... siOnCreateShader? i generated this event from the
>>>>> wizard and it seems to log a lot of relevant info. also there is
>>>>> siOnConnectShader
>>>>>
>>>>> " *Question*: Can material assignment happen without this command
>>>>> being run? In other words, is catching this command sufficient for
>>>>> monitoring all the ways that a material can be assigned to an object? I'm
>>>>> not very experienced with using Softimage, but I know that in Maya there
>>>>> are a million and one ways to assign materials. "
>>>>>
>>>>> -one could change the shader graph but not the material assignment.
>>>>> -one could 'drag and drop' a material from the material view in the
>>>>> explorer on to an object. that calls 'CopyPaste()' command. i have always
>>>>> been on the fence whether that command is good or bad)
>>>>>
>>>>>
>>>>> On Fri, May 4, 2012 at 4:39 PM, Nicolas Burtnyk <
>>>>> nico...@redshift3d.com> wrote:
>>>>>
>>>>>> Hi list people!
>>>>>>
>>>>>> For my custom renderer, I'm trying to keep track of when materials
>>>>>> get assigned to objects.
>>>>>> This is part of an overall system which tracks changes to the scene
>>>>>> so that I can incrementally process only the parts of the scene that
>>>>>> change
>>>>>> between renders.
>>>>>>
>>>>>> Since there is no specific event that gets fired when a material is
>>>>>> assigned to an object (that I know of - please correct me if I'm wrong!),
>>>>>> I'm trying to use *siOnEndCommand *to catch the *AssignMaterial *command.
>>>>>> *By the way Softimage devs: please add a OnMaterialAssigned event :)
>>>>>> *
>>>>>>
>>>>>> I have 1 question and 1 issue:
>>>>>>
>>>>>> *Question*: Can material assignment happen without this command
>>>>>> being run? In other words, is catching this command sufficient for
>>>>>> monitoring all the ways that a material can be assigned to an object?
>>>>>> I'm
>>>>>> not very experienced with using Softimage, but I know that in Maya there
>>>>>> are a million and one ways to assign materials.
>>>>>>
>>>>>> *Issue*: While I'm correctly receiving the ApplyMaterial command in
>>>>>> the siOnEndCommand callback, I'm having trouble deciphering the command
>>>>>> arguments.
>>>>>> Basically I want to know the Material that was assigned and the
>>>>>> Object(s) it was assigned to. Simple, right?
>>>>>> In the siOnEndCommand callback, I get the "Command" attribute from
>>>>>> the context and create a Command object from it. I then retreive the
>>>>>> arguments using Command::GetArguments(). The ArgumentArray always has a
>>>>>> count of 2 (whether I assign the material to 1 or more objects).
>>>>>> The second argument (ActionWhenLocalMaterialsOverlap) is irrelevant
>>>>>> to me. The first argument is a CValueArray that has a CRef for the
>>>>>> Material being assigned as its first element and some mysterious CRef as
>>>>>> its second item. *My issue is that I don't know what to do with
>>>>>> this strange CRef*.
>>>>>>
>>>>>> Here is a concrete example:
>>>>>>
>>>>>> I have 2 objects and 1 material in my scene and assign the material
>>>>>> to both objects in a single action:
>>>>>> Application.AssignMaterial("Sources.Materials.DefaultLib.Material,sphere,cylinder",
>>>>>> "siLetLocalMaterialsOverlap")
>>>>>>
>>>>>> In the siOnEndCommand callback I get:
>>>>>>
>>>>>> Command(Context(in_ctxt).GetAttribute(L"Command")).GetArguments()[0].GetValue()returns
>>>>>> a CValueArray with 2 items.
>>>>>>
>>>>>> Item 0 : CValue, m_t=siRef - this is a CRef to the Material being
>>>>>> assigned, as expected. GetAsText() return
>>>>>> "Sources.Materials.DefaultLib.Material" and GetClassIDName() returns
>>>>>> "Material". Good to go.
>>>>>>
>>>>>> Item 1 : CValue, m_t=siRef - this is some kind of weird CRef that I
>>>>>> don't know how to handle. GetAsText() returns "sphere,cylinder" and
>>>>>> GetClassIDName() returns "Object". What do I do now? How can I get
>>>>>> those
>>>>>> objects as CRefs? Do I have to tokenize the string and parse out the
>>>>>> object names? It's not hard, but I'd like to do something cleaner if
>>>>>> possible.
>>>>>>
>>>>>> Thanks!!
>>>>>>
>>>>>> -Nicolas
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>
