Geometry on points not orientated to surface

[salik]

Hi all,

I have a diagonal plane where I have made a particle flow.
While running the sim, I saw that all the particle normals are 'pointing outwards', perpendicular to the plane.

I create a sphere, deform it then uses a 'copytopints' node, connecting the sphere and the particles, I saw that the sphere generated on those points are not oriented/ aligned to the surface.

Any ideas?

[Jesper Rahlff]

can you share you file?

[dgani]

In this case, your particles most likely have a velocity attribute. When velocity is present, copy to points prioritizes that value over the normal.

You can try promoting your normal value to the orient attribute in a wrangle. Something like @orient = dihedral({0,1,0}, @N)

[salik]

Hi all,

 

 

In the above image, you can see that the sphere is shown as vertically up against a slope surface.

Then I try to conform the rotation by changing the sphere orientation to use Z-axis, and so I got the following:

Feel free to correct me if I am wrong, but I had thought this will be better when it is cooking the node - vdbsmooth. In any case, still, the sphere is still not being oriented/ conformed to the surface (you can see in the above image, the sphere on the left foreground)

This is my file - particles_orientation.hip

Edited March 29, 2018 by salik

[woodenduck]

if you add some point normals to your grid before the scatter and ray, you will see spheres correctly oriented. 

Cheers, 

WD

[salik]

40 minutes ago, woodenduck said:

if you add some point normals to your grid before the scatter and ray, you will see spheres correctly oriented. 

Cheers, 

WD

That seems to have work! Now I have a question - when will I need to add in the use of Normal node?

I asked because, initially via the viewport, I was given the impression that all the points generated have normals as defined by the blue lines...

Edited March 29, 2018 by salik

[woodenduck]

In order to get the normals correctly oriented you need to calculate them before the scatter. This is because the orientation of the polygons associated with a given point determine the normals direction.