Day: May 19, 2017

The following notes are taken from the Content Creation User Group meeting, held on  Thursday, May 18th, 2017 at 1:00pm SLT at the the Hippotropolis Camp Fire Circle. The meeting is chaired by Vir Linden, and agenda notes, etc, are available on the Content Creation User Group wiki page.

Audio extracts are provided within the text, covering the core points of the meeting. Please note, however, that comments are not necessarily presented in the chronological order in which they were discussed in the meeting. Instead, I have tried to place a number of related comments by Vir on specific topics into single audio extracts and with their associated notes, in the hope of making those topics easier to follow, and without changing the context of the comments themselves.  If you would prefer to listen to the discussion and comments in the order the meeting unfolded, I have embedded a video recorded at the meeting by Medhue Simoni. My thanks to him making it available.

Supplemental Animations

While this is now an adopted project, the focus has been on animated objects, and so there is no significant progress on this work at present.

Applying Baked Textures to Mesh Avatars

No movement on this.

Animated Objects

Vir has spent most of the week since the last meeting working on animated objects and developing prototypes and looking at proof-of-concept to see how objects might be animated using the avatar skeleton. He describes the results thus far as encouraging whilst also pointing out it is still early days with the work, so it is still far too early to determine what the final architecture will be.

The viewer already has a notion of an avatar without a human operator, which is notably seen when uploading an avatar mesh or animation. This notional avatar isn’t rendered graphically, but is oriented using transforms so that an object can use it as a source of joint motions. This is not necessarily how things will work with any finished product, but it is enough to demonstrate what might be possible.

Currently, Vir is working with single object rigged meshes, and would be happy to receive similar models, preferably with associated animation, if people have anything they believe would be useful for helping with these tests.

It is hoped that “being animated” will be an additional property which does not require a new mesh upload option, so that any rigged mesh for which you have Edit permissions for can be set to use the property  so that it can be driven by its own animations.  Currently:

• This will likely mean the object will no longer be attachable to an avatar
• It has yet to be determined if this property will be a new prim type or an additional field added to an existing object, etc
• It will not require any changes to the current mesh uploader; the property to convert a mesh to an animated object can be set post upload.

A suggestion was made that the animated mesh should use its own skeleton when independently rezzed in-world, but a sub-set of a controlling avatar’s skeleton if it is attached. This would allow things like animated horses to be rezzed in-world and then sat on for riding or pets to be “picked up” and carried,  as is currently the case with some scripted animals already.

The testing carried out thus far hasn’t looked at animated attachments, although Vir appreciates the potential in having them. However, there are concerns over potential additional performance impacts, the risk of bone conflicts (what happens if your avatar is already using one or more bones some something and these same bones are used by an animated attachment).

While not ruling the potential out, Vir’s tests so far haven’t encompassed animated attachments to determine what issue might arise.  There are also other factors involved in avatar control which need to be looked at with animated objects: hover height, offsets, position, etc., all of which might affect how an animated object might be seen / behave.

Scripting / LSL Commands

The current work has not so far looked at LSL commands or command sets for the new capability. However the intent remains that scripts for controlling an animated object will be held within the inventory for that object, and able to call animations for the object also contained within the object’s inventory, so things are not straying too far from what can already be doing vis scripted control of in-world objects.

Performance Impact

Similarly, it is hard at this point to know what the likely performance hit might be. Bento has shown that adding more bones to the avatar skeleton doesn’t create a notable performance hit, so providing a skeleton for in-world objects shouldn’t cause any greater impact than a basic avatar. However, associating a rigged mesh object with than skeleton, then animating the joints, etc., will have an impact, particularly if a lot of animated objects are used in any given place.

This is something that will be looked at in greater detail once there is a project viewer available for testing alongside any server-side updates, although the Lab doesn’t intend to make it easy for a region to be spammed with multiple versions of an animated object, and this may in part be linked to the Land Impact associated with such objects.

Attachment Points on Animated Objects and Linksets with Animated Objects

While attachment points are also joints within the skeleton being used by an animated object, and so can be animated, they would not actually support having other objects attached to them, as the animated object doesn’t have links to other objects in the way an avatar does.

An animated objects could be a linkset of rigged meshes which are identified as a single object, with all of the rigged meshes referencing the same skeleton. Things might be more difficult if static mesh objects form a part of the object, as it is not clear how the positioning of these would be controlled, and more testing is required along these lines.

Body Shapes and Animation Scaling

Requests were made to allow animated objects to have body shapes (which would allow slider support, etc.), and  / or animation scaling.

Because of the changes that would be involved in both, coupled with the potential for conflicts in the case of animation scaling, Vir does not see either as being part of this work – as previously noted, assigning a body shape to an animated object would impact a number of other back-end systems (such as the baking service), adding significant overheads to the project.

As such, the Lab would rather keep the work focused, building on something that could be rolled-out relatively quickly, and then iterated upon. However, one option that might be considered is having some kind of root node scale, based on the scale of the animated object that would size the skeleton to the scale of the object, rather than vice versa, possibly by altering how the mPelvis bone is managed for such objects.

[56:37-1:02:30] The final part of the meeting delved into the relative efficiency of mesh and sculpts, and matrix maths on CPUs / GPUs, and the complexities of rendering animated objects, together with a reminder that object rendering costs are currently being re-examined.

Other Items

In-World Mesh Editing?

[41:00-55:55] Maxwell Graf raises the idea of having a simple in-world mesh editor / enhancements to the editing tools which would allow creators to adjust individual face, edge or point in an object, presenting a reason for mesh creators to spend more time in-world and which might allow non-mesh builders more flexibility in what they can do as well.

The current toolset  – mesh uploader and editing tools – would not support such a move. There are also a number of potential gotchas on a technical level which would need to be understood and dealt with, and in order for the Lab to consider such a project, any proposal would have to consider the smallest subset of capabilities available in dedicated mesh creation / editing tools like Blender and Maya that would be useful to have in-world, so that it might be possible to define the overall scope of the work required in terms of resources, etc., and what the overall return might be on the effort taken.

Based on the conversation, Max is going to try to put together a feature request / proposal, even if only for the purposes of future discussion.