drop issue

[roberttt]

hi guys how can i slide that drop on the surface?

 

test.hiplc

[StepbyStepVFX]

I think you can do it with a POP Wrangle, plugging your geometry on one of the input of the DOP network.

You calculate distance of the particle to the surface of the object (xyzdist return the distance and you can pass a vector and an integer to know what is the closest point), and if it is really close to 0, then you replace the x and z coordinates of the particle position by the one of the nearest point on the sphere (using the uv and prim number returned by the xyzdist). Therefore y keeps being updated (gravity etc.), but once there is a contact with the sphere, the drop stick to it.

If you want the drop to fall and stop sticking, you can test its position in y vs. the position of the sphere, or tets a condition vs. the slope of the tangent of the contact point with the sphere (you would expect the drop to stick while the tangent is quite vertical, but once you have reached the inferior quarter of the sphere, the drop should fall again... no ?). By the way, to get the tangent, I would use primuv (with uv and prim number given by xyzdist, again) to get the normal of the sphere, and make a cross product with an horizontal vector (and then check the cosine of that tangent with up vector...).

Hope this helps.

[roberttt]

Sorry i am still beginner can u show on my hip file?

[StepbyStepVFX]

Hope I understood what you wanted :-)

you can play with the DistMax threshold (distance from the surface of the sphere at which they start to stick and drip along the sphere).

test_v2.hiplc

[roberttt]

thank you