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Unexpected Forward Vector

ポケレゲ (LOOT)

March 15, 2017 02:59

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Hello everyone,

 

I'm having issues on getting the forward vector of objects.

The image below is a custom mesh printing the forward vector.

Here's another image that uses a mesh from the Sansar store.

The two objects seems to be printing their forward vectors as world space down.

Now here's another object that's from the Sansar store:

Now this object is printing the forward vector as world space forward, which I am expecting.

 

Am I importing my models incorrectly or there is something to consider for determining the forward vector? Also what is the W dimension being used for?

3 comments

• 0
  
  Donnie April 17, 2017 09:32

  W is the fourth axis of a quaternion, usually. Your issue seems likely to be a rotation you gave the object in your 3D software and wasn't frozen. Moreover, in the export settings of FBX, usually there's a section for "axis conversion", so you should also make sure that it matches your actual scene's world orientation, before you export.

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  Donnie April 17, 2017 09:39

  From your screenshots, it looks to me that the forward vector should be +Y?

• 0
  
  Ethos Erlanger June 12, 2017 18:09

  I agree! To test this object orientation, I created a new cube and textured it with the axis orientation that was used in Blender to create it. It was never rotated in Blender prior to being exported. When I imported this cube into Sansar, I find that Y+ faces the camera assuming that the camera is looking out of the avatar as he faces the default orientation of the creator when they enter edit mode. (Let's call this North.) And X+ faces West. This is 180 degrees from my expectation and requires me to rotated everything that I make.

  Blender has export options that should allow us to re-orient the items being exported, but they fail to make any difference in what Sansar does when it imports the object. They all come in the same. See my test cube(s) here: https://atlas.sansar.com/experiences/ethoserlanger/blender-axes-cube