Observations while playing around

[musbel]

The following is a short list of observations and general questions which may be irrelevant (or simply a case of misunderstanding) due to my limited exposure to Gaffer:

• Tight coupling between the nodes and the generated scene graph feels prone to future issues and forces the user to be more meticulous about where the nodes are placed as any change to the location of nodes will affect the scene graph state. This means the scene graph location is implicitly created whereas an explicit scene graph location, which decouples it from the node graph, might offer more flexibility and allow merging and grouping strategies.
• It is slightly confusing that adding nodes downstream may re-parent the scene graph structure. For instance, adding a new geometry node will change the scene graph location path which may have been used in assignments (path filter). The change in the path filter is not reflected which makes it confusing for the user and will be a bit cumbersome as the scene grows. Consequently, new nodes sometimes changed the rendered image due to broken camera constraint and material assignments.
• Cannot override shader parameters downstream. Having shaders/materials as scene graph locations could perhaps help here.
• Can the look be baked and shared across shots?
• A bit difficult to track shader assignments in the scene inspector as changing the shading node name was not reflected in the inspector. Instead, the assignment still shows up as the shader name which makes it trickier to see which node it derived from.
• No attribute history displaying e.g. where assignments/overrides originate from.
• Cannot view through cameras/lights.
• Transformations and parameter/attribute values (e.g. cone angle) cannot be modified in the viewer using manipulators.
• Would benefit from logging tools (and a render log). The render log information could be a bit clearer at times. An example is an out of date path filter after adding a new node where the scene graph is re-parented. The render throws an exception but does not state what went wrong so you have to go through the nodes by hand to see if any assignments are broken.
• Would be good if the nodes would e.g. glow or somehow indicate if their state was invalid, particularly when the node graph grows and finding issues becomes more difficult.
• Would be nice to have context stacks for nodes.
• Would be nice to be able to easily render from any node in the scene (without a render node).
• The render node does not seem to be connected to the scene graph hierarchy in the same way as other nodes as the scene graph disappears when viewing through it.
• Would benefit from default attributes as everything has to be explicitly set up to work.
• Can't seem to be able to dump out a render debug output (e.g. rib/ass) from arbitrary nodes/scene graph location.
• Group attributes would be useful, and attribute states (e.g. globally inherited).
• It is nice that you can build network materials but it seems the node is not abstracted from the shader itself which has to be physically plugged in the node graph to a shader assignment. Does that cause issues when overriding the assignments downstream?
• Would be useful to allow exposing the shader network in a public interface instead of having the artists dig through the underlying network.
• Might be more flexible to use renderer attributes instead of using a renderer specific render node.
• Is it possible to integrate a publishing system into Gaffer?
• Is it possible to integrate a farm dispatcher or custom render launch modes?
• Would be good to have more examples, e.g. with instancing and renderer procedural work flows.
• Examples menu is empty.
• Can't seem to be able to modify the layout.
• Would be nice to have a evaluation/viewing state badges on the nodes (e.g. Houdini) instead of having to use the pinning option.
• Selecting an object in the viewer does not change the Node editor to allow editing the corresponding node parameters.
• The scene graph and attributes don’t show up sometimes. Have to jump back and forth to get it back.
• Cannot type negative numbers in the parameter widget without highlighting/deleting the existing number.
• Would be useful to see the scene graph location type in the scene hierarchy (and perhaps configurable to show additional properties).

[johnhaddon]

Thanks for the detailed notes - they're great to have. Many of them seem to be useful discussion points so I'll post my replies to those on the developer mailing list which is better suited to that purpose. This issue tracker is for creating individual work items which we can prioritise and add to milestones so one ticket with many items is hard for us to manage - we'll make individual tickets for each thing that comes out of the discussion.

[bentoogood]

A bit difficult to track shader assignments in the scene inspector as changing the shading node name was not reflected in the inspector. Instead, the assignment still shows up as the shader name which makes it trickier to see which node it derived from.

#335

[bentoogood]

Cannot view through cameras/lights.

#49

[bentoogood]

Would benefit from logging tools (and a render log). The render log information could be a bit clearer at times. An example is an out of date path filter after adding a new node where the scene graph is re-parented. The render throws an exception but does not state what went wrong so you have to go through the nodes by hand to see if any assignments are broken.

kinda related #139

[bentoogood]

Would be useful to see the scene graph location type in the scene hierarchy (and perhaps configurable to show additional properties).

#80