That doesn’t tell me what has changed or why my operator is being called.
If my operator has 7 inputs of various data types, I would like to know that input 4 was changed so I can skip any work not related to input 4. If I have to dig through all the input data and compare it to my cached userdata, then it kind of defeats the purpose, no? Example: my operator takes several inputs: - 1 Polygon mesh - 2 NURBS Surfaces - 4 Weight maps My operator has 1 output: - Clone of input polygon mesh This operator is a deformer which does closest location searches between the polygon mesh’s vertices and the 2 nurbs surfaces. For each closest location operation, I must perform additional math to convert between Non-Uniform and Uniform parameterized space. Overall, It’s very expensive. If Softimage can tell my operator that only vertices 4, 5, and 23 were changed on the input polygon mesh, that means I only have to do 3 closest location searches, not N (where N=number of points on mesh). That’s huge savings and a major boon to performance. Likewise, if Softimage tells me only one of the NURBS Surfaces was modified, then I only need to perform the tail-end of the calculations to deform the output polygon mesh. Also huge savings. Some of the overhead of the operator is pulling information from the scene to be processed, such as point positions array, getting the NURBS samples arrays, or the 4 weight maps. Even if I compare that data to my cache and discover almost nothing changes but a few items, that’s still significant amount of work the operator must perform that could otherwise be skipped with proper notification. Besides ways to skip unnecessary work, I’m looking for ways to avoid storing mass amounts of redundant data in an operator cache. Matt From: softimage-boun...@listproc.autodesk.com [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Jon Swindells Sent: Tuesday, April 15, 2014 7:56 PM To: softimage@listproc.autodesk.com Subject: Re: SDK: detecting changes in Custom Operator (C++) probably stating the obvious here but, wouldn't you just cache the deltas (blob, userdata etc) and use that for your sparse/dirty call on the next eval cycle ? -- Jon Swindells jon_swinde...@fastmail.fm<mailto:jon_swinde...@fastmail.fm> On Wed, Apr 16, 2014, at 05:15 AM, Matt Lind wrote: Is there any way to detect what exactly has changed between calls to a C++ custom operator? (eg; which inputs were dirtied?) I have a custom operator (deformer) which has several inputs. Each time an input is dirtied, the custom operator must iterate through all the point positions, samples (UV), and weight maps from the polygon mesh during each update, and modify that data using information obtained from the other inputs. While my operator computes the correct result, it comes with significant overhead. 95% of the time, less than 5% of polygon mesh’s points are modified. It seems like a waste to iterate through all those points when only a tiny bit actually changes requiring processing. I would like to only process points where the positions, samples, and/or weight maps have changed between updates and skip the rest. Is that information available to a custom operator? If so, how do I access it? To pre-emptively answer the obvious question that will be asked – No, I cannot do this in ICE because my custom operator must work with NURBS in a particular fashion that is not supported by ICE. Matt
