[Solved] Grid to sphere with Bend Sop

[Aizatulin]

@flcc v@pt_uv is working for me and using point split (with vertex uv) to create uv islands. The creep sop may help aswell, if you convert your uv values into points positions. 

 

 

 

 

uv_creep.hipnc

[flcc]

@Aizatulin Thanks, It works perfectly like that.

But is it juste another method or does that mean that uvsample is not the way to go for this task ?
I ask because you say v@pt_uv is working for you. I try to split point and vertex before the wrangle (in my previous exemple), but no way.

Just trying to understand.

[Aizatulin]

I was a bit unclear, v@pt_uv was related to your previous example to avoid the spiral. If you want to use plit points you can use the uv value directly, instead of converting them to point position. This was just to make it usable for the creep sop. uvsample is useful, if your target geometry is non parametric, which has no intrinsic uv values, which can be called with primuv() - to get every point of the surface by a (u,v) pair. uvsample is more an optimizer, which tries to find the best fitting uv-value for your input uvw vector. This uv-value can be for example a vertex/point uv-value (non intrinsic). uvsample will give you the (interpolated) point (or point/vertex attribute) on the geometry, which uv value has the closest distance to the input uvw vector. But the problem is, that there maybe multiple optima or the optimum is far away from the desired uvw vector etc... .

https://www.sidefx.com/docs/houdini/vex/functions/uvsample.html

or check Konstantins link.

 

Here is another modificaction of your previous example.

sphere_pos real uv_flcc.hipnc

[flcc]

@Aizatulin  Thank you for that very clear explanation.
I got the intrinsic meaning now.
Meanwhile, I found one of the problems... a typo !  @pt_uv in place of v@pt_uv. I still fall into that trap sometime.
And yes i've carelly checked constantin link.
I've learn a lot with this "little" problem
Thank you for your time
Cheers
F

[vinyvince]

On 14/02/2020 at 3:38 PM, Atom said:

Here is another offering.

Three UV mapped spheres that unfold to different grid aspect ratios. A 16:9, 4:3, and 32:9.

These are pre-animated Alembic files, not procedural at all.

ap_UV_spheres_unfold_to_plane.zip

 

I always hate mapping a precise patern on sphere, planet, without breaking, and without distortion at each poles. How do you guys deal with that stress?

Here's one way but in substance.. Using point deform to compensate the distortion on each poles is what im thinking right now but may there there is a better way?

@Atom @f1480187@konstantin magnus

 

[mystyphy]

On 2/13/2020 at 4:02 AM, flcc said:

Just a detail but as is, the bend values don't reflect the actual bending proportions. (bend1 angle x1 bend2 angle x2)

If you constrain the capture length to the grid size, then you get correct proportions, and most importantly you can change the grid size freely

Grid_to_Sphere F.hiplc

I don't think I get the intended result when opening this file.

 

[jfiola]

On 2021-08-22 at 6:16 PM, mystyphy said:

I don't think I get the intended result when opening this file.

Activating "Deform in both directions" on the Bend nodes worked for me in H18.5.672