Adding polygons/subdivision base on attribute

   8302   6   1
User Avatar
Member
24 posts
Joined: 6月 2009
Offline
For example you have a low poly model. With a paintsop you draw attribute on it. Can you use this attribute to procedurally add polygons/subdivide/remesh geometry only where you want?
User Avatar
スタッフ
2540 posts
Joined: 7月 2005
Offline
Yes. Each SOP may have it's own group type requirement: points, primitives, edges…

See the example file for a couple different ways.

Uses a single painted point attribute of your choosing. Most refinement type SOPs take primitive groups so you need to promote the point attribute to primitive attribute either for direct use in group fields or in a Group Expression SOP.

Attachments:
local_prim_refinement_with_point_attribute.hip (1.2 MB)

There's at least one school like the old school!
User Avatar
Member
24 posts
Joined: 6月 2009
Offline
jeff
Yes. Each SOP may have it's own group type requirement: points, primitives, edges…

See the example file for a couple different ways.

Uses a single painted point attribute of your choosing. Most refinement type SOPs take primitive groups so you need to promote the point attribute to primitive attribute either for direct use in group fields or in a Group Expression SOP.
Thanks a lot, i came to much less efficient variant, with subdividing geometry first then deleting parts without color attribute and combining results with a lowpoly mesh after that.
Edited by sandzuro - 2017年3月9日 15:59:15
User Avatar
Member
21 posts
Joined: 7月 2017
Offline
Brilliant stuff, thank you so much Jeff!
User Avatar
Member
1 posts
Joined: 1月 2020
Offline
old_school
Yes. Each SOP may have it's own group type requirement: points, primitives, edges…

See the example file for a couple different ways.

Uses a single painted point attribute of your choosing. Most refinement type SOPs take primitive groups so you need to promote the point attribute to primitive attribute either for direct use in group fields or in a Group Expression SOP.


Thank you for the example

I am trying to do something similar but with a Mask. I am still struggling to figure out why it doesn't work as expected.
User Avatar
Member
411 posts
Joined: 6月 2015
Offline
old_school
Yes. Each SOP may have it's own group type requirement: points, primitives, edges...

See the example file for a couple different ways.

Uses a single painted point attribute of your choosing. Most refinement type SOPs take primitive groups so you need to promote the point attribute to primitive attribute either for direct use in group fields or in a Group Expression SOP.


Correct me if i'm wrong, but this method does not allow to use a integer attribute to define the level of subdivision depth per primitive, correct? I'm desperately trying to increase the amount of subdivision around a specific object (ocean around a boat), but it is not working. Why is that? And i do want polygons, i'm not planning to render that ocean with displacement, i need the polys close to the boat and less and less further away in the background.

Cheers,

A.
User Avatar
Member
4730 posts
Joined: 2月 2012
Offline
Adriano
old_school
Yes. Each SOP may have it's own group type requirement: points, primitives, edges...

See the example file for a couple different ways.

Uses a single painted point attribute of your choosing. Most refinement type SOPs take primitive groups so you need to promote the point attribute to primitive attribute either for direct use in group fields or in a Group Expression SOP.


Correct me if i'm wrong, but this method does not allow to use a integer attribute to define the level of subdivision depth per primitive, correct? I'm desperately trying to increase the amount of subdivision around a specific object (ocean around a boat), but it is not working. Why is that? And i do want polygons, i'm not planning to render that ocean with displacement, i need the polys close to the boat and less and less further away in the background.

Cheers,

A.

I would recommend adaptive subdivision rather than trying to store final subdivision levels as an attribute, as that won't have enough resolution to have fine subdivisions. I used this approach on ocean interactions many times:

Senior FX TD @ Industrial Light & Magic
Get to the NEXT level in Houdini & VEX with Pragmatic VEX! [www.pragmatic-vfx.com]

youtube.com/@pragmaticvfx | patreon.com/animatrix | pragmaticvfx.gumroad.com
  • Quick Links