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Building, Skyboxes, Scripting - Tie it all together

Ethos Erlanger

August 18, 2017 18:49

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We need an OFFICIAL explanation of the axis orientations that do not align with each other. A Skybox that is created based on the published Sansar Skybox template does not show the same axis orientation as the axis that we use to translate and rotate objects in edit mode.

The official Skybox template shows +Z as forward and "North". We use +Z as up when we build. That mismatch needs to be explained in OFFICIAL documentation.

While I do not do scripting that involves vectors, it is reported by other creators that those vectors are not oriented in a way that matches our building orientation.

Documenting this topic will reveal to Linden Lab the discrepancies. And if there are no plans to ever change these discrepancies, just be open and honest with us by telling us that this issue has no priority. Document how it is now and how it will remain for the foreseeable future.

8 comments

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  Galen August 18, 2017 19:11

  I'm finding that the vectors in my scripts fit the world coordinate system just fine. I think Gindipple found that he had trouble with the coordinate system used for Avatar attachments.

  Edited by Galen August 18, 2017 19:12
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  OldVamp August 18, 2017 20:47

  

  if you are facing north (-y), you will be able to read these in the correct direction by looking up and down.

  Cube should have inward pointing faces.

   

  some files:

  https://www.dropbox.com/s/803nkxewst6tcvz/blender%20skybox.fbx?dl=0

  https://www.dropbox.com/s/v70ciyoi68haxtd/SansarSkyBoxTemplateBlender.exr?dl=0

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  Ethos Erlanger August 18, 2017 23:44

  @OldVamp I am intrigued that you would do this comparison of the axis orientation from two different products. Now, lets please get back to the one product that matters here... Sansar. I am very interested to see what evidence might be found from any Linden Lab documentation that -Y is North.

  IF the default value for North in Sansar is -Y, we could begin to sort out why the Sansar Skybox template is printed with +Z and North and the word "front" all on the same square. Have you some insight on this that I may have missed in my search of the Sansar Knowledge Base?

  We should not use the orientation from any other program to infer the orientation in Sansar.

  Edited by Ethos Erlanger August 18, 2017 23:53
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  Ethos Erlanger August 19, 2017 00:04

  Also note that I believe that "front" is the default way that my camera faces every time I enter a default Sansar scene in edit mode using a desktop computer. It just seems safe to believe that edit mode is the one mode that matters here for this discussion. And based on all of my testing of the edit mode, there is only one way the camera faces until we move the camera.

  We enter the scene facing the way that Linden Lab has us facing. And, by the way, the way we face is +Y based on the way we would move objects on the grid provided to us by Linden Lab. Control over this is clearly out of our hands.

  Edited by Ethos Erlanger August 19, 2017 00:07
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  OldVamp August 19, 2017 04:13

  I used a different product for comparison because my point is, north changes per software.

  The official template was likely made in Maya where +Z is actually what other programs define as the Y axis.

  

  The fact that it is called "North" does not matter. All that matters is that you figure out which axis match up in the program you are using.

  Edited by OldVamp August 19, 2017 04:16
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  Gindipple August 19, 2017 05:26

  An important thing to realize is there can be many coordinate systems in use at once. For example we know for sure the object's world coordinates are different from the avatar attachments system. There could be 6 different systems employed at various aspects.

  This is perfectly viable and only becomes confusing when you bring the 2 systems together to interact. You just have to use the correct transformation from one system to the other. A basic rotation quaternian will do exactly this for you. It's hard as an architect to pull together different tools and expect them all to use the same system. For example Havok may use a different one than the front end Game engine. You simply apply a transformation as each thing passes from one to the other. You can see this very thing happen when you click World Coordinates in the editor. It's just applying a transformation.

  NOTE: this is different from the post I made about the internal vector directions such as Vector.Left, Vector.Right, Vector.Forward and Vector.Back being kinda messed up. One would think they should apply to the scene object's world coordinates, but the don't seem to. Maybe they apply to the avatar attachment coordinate system lol which just makes them kinda useless, but no biggie you aren't obligated to use them vectors, it's just a nice to have.

   

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  Gindipple August 19, 2017 19:29

  This is a perfect example of multiple coordinate systems in use at once.

  The game board and the scoreboard are at different rotations from each other and both are different from the world coordinates. So when I put up a new score I have to perform a transformation each time.

  
  https://gyazo.com/18d8ba760c99f8fa458f90c5a6d5d556

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  Ethos Erlanger August 19, 2017 21:36

  Let's all retrace our steps here and begin at the top of the page where it says:  Sansar > Community > Documentation.

  There you will find this: "Is there documentation you would like to see added to the Knowledge Base, or some more details you think would be beneficial to exisiting articles? Share your thoughts here."

  And in office hours and product meetups we have been encouraged to request documentation in this forum.

  And from that invitation to ask for documentation, I believe they really wanted to know what I want them to document. I wrote in my first post a simple request for an OFFICIAL explanation of the axis orientations that do not align with each other.

  Let's all stop trying to do their documentation for them. They are the ones who created the skybox template that is shown here:
  When I used this template it did not look anything like the Sansar global coordinate system used for building. That template includes words like North, South, East, and West. So, I thought those words really mattered. And if this is indeed a Maya skybox template, let Sansar tell us so. Then they might wish to tell us that if we use the Sansar Global Axis for building, then the three letters seen on the Maya template skybox are meaningless and are not meant to mean the same as the same three letters X, Y, and Z that we all know and love called the Cartesian Coordinate System that we all use regularly for building in Sansar. The one with +Z that means UP. Really.... Z is UP in Sansar. Don't take my word for it. Test it for yourself.

  But, they have not told us about the skybox axis. They are the ones who asked us to ask for documentation. They did not invite us to create our own answer or to guess how or why they designed a skybox that uses a different axis from the building coordinate system. This is not a WIKI where we are all equal contributors.

  This should not be a guessing game. Let's wait for Linden Lab to answer with their own documentation.