Hmm, probably this question is to special or bad described?

I only want to get the best possible result during my calculations for the vertices, faces and normals.

But maybe it is not only a thing on my side but also on the way how wikitude is doing the transformation from the opengl coordinate system to a ?real world coordinate system, probably wgs84 or pseudo mercator? or vice versa?

I only want to get the best possible result during my calculations for the vertices, faces and normals.

But maybe it is not only a thing on my side but also on the way how wikitude is doing the transformation from the opengl coordinate system to a ?real world coordinate system, probably wgs84 or pseudo mercator? or vice versa?

## Robert Gregat

Hi, I have a couple of questions regarding the creation of 3D-Models.

1.) What kind of coordinate system is used in wikitude? For the positioning it is necessary to use WGS84 (geography) Coordinates. On the other side it is also possible to translate an object but with metric values, which makes sense because to do that with geographic values is horrible with all these decimal places.

2.) With the first question/assumption in mind I would think that I need a coordinate reference system which is valid for the most part of the world, for example the pseudo mercator reference system, to create my 3D-Models. I know, that every 3D-Model has an independent coordinate system which is anchored around one point (the origin) which will be used later to position it in the ar scene. But to create the 3D-Models geographical correct I need the correct coordinate system to do my calculations.

3.) Why I think of the pseudo mercator reference system? Well it is a metric coordinate system and I guess that you transform the geography coordinate for the positioning (where a 3D-Model is anchored) in your ?AR metric reference system? some how.

4.) But what is still a question mark in my mind, is the rotation and actual the scale which I have to respect if I want a true representation of my 3D-Model in the real world. What I mean with this statement. If I have a simple rectangle in the real world with the dimension of 3*2 m and a certain rotation, well than I want to create a 3D-Model which fits at the end exactly on this real world rectangle (I purposely left out the accuracy of the positioning of a mobile device).

I know this are a few questions but I hope that you can shed some light.