Export Point format

General
1

Hi Guys,

Using the Alex scan head and base topology we have exported a Point file with several entries. We were hoping these would be xyz coordinates, but the first vector is huge.
Can you explain what these values are and if we are doing anything wrong??

Here is an example:
[[607818,0.57415908575057983,0.21377584338188171],[18414,0.50028455257415771,0.32517749071121216],…]

Thanks

Andy M

2

Hello Andy,

The points exported from Wrap/WrapX are not points in 3D space but points on surface. With this representation you can apply point selection from one object to point selection from other object provided that their topologies are the same. We encode points on surface with 3 values:

[ol]- Triangle index (if the model contains polygons with more then 3 vertices we triangulate it with naive fan triangulation with origin in the first vertex of the polygon)

  • First barycentric coordinate
  • Second barycentric coordinate[/ol]

I know that this is quite complicated to use so in WrapX we have a function called pointToPointOnTriangle (http://russian3dscanner.com/docs/WrapX/wrap.Geom.pointToPointOnTriangle.html) that converts points in 3D space to this representation.
We will implement it in Wrap3 a little bit later.

Please let me know if you need more help on this.

3

Hello,

Can you take me through how I might export several points (matching marker points on neutral face scan) created in Maya to be used in a Wrap3 recipe json file executed from WrapX Command/ Console?

Best,

Dan

4

Hello Dan,

I think it’s easier to do that in WrapX. Please export the points as 3D coordinates, then use wrap.Geom.pointToPointOnTriangle
http://www.russian3dscanner.com/docs/WrapX/wrap.Geom.pointToPointOnTriangle.html
function. You can save the list of PointOnTriangle to a file and then load this file in Wrap3 if needed.

5

Hi Andrew,

Is this function described above implemented in Wrap 3 by now? Or would we need to use WrapX still?