VDB from Polygons: non-watertight geos?

   747   7   3
User Avatar
Member
1007 posts
Joined: April 2017
Offline
Hi!

I'm converting an asset to VDB but some geos have no thickness (non-watertight). I remember seing some node/option to deal with those geos. It would give it thickness in a smart way... Know anything about this?

-Olivier
User Avatar
Member
2537 posts
Joined: June 2008
Offline
I always start with a polyextrude and add a small width. Sometimes it is easier just to model a watertight likeness to supply as a collider.
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
User Avatar
Member
679 posts
Joined: Feb. 2017
Offline
Geo seal by momme is a valid option:
https://momme.gumroad.com/l/geoseal?layout=profile [momme.gumroad.com]
Cheers
CYTE
User Avatar
Member
7722 posts
Joined: July 2005
Online
Another option might be Tet Embed followed by a VDB From Polygons.

EDIT: And also turn off Enlarge Input Mesh on the Tet Embed
Edited by edward - March 13, 2024 17:04:23
User Avatar
Member
7722 posts
Joined: July 2005
Online
Or use Tet Conform instead of Tet Embed.
User Avatar
Member
238 posts
Joined: March 2013
Offline
Vdb topology SDF will reconstruct the data, but it will be larger in size.
The trick is to appply a reshape SDF and erode 1-1.5, convert VDB to poly and us negative ISO offset values.
then you can do another VDB from polygons, from a nice watertight piece of geo, this setup of steps will get you
very close to the original source mesh.
I'm not lying, I'm writing fiction with my mouth.
User Avatar
Member
1007 posts
Joined: April 2017
Offline
Alright, thanks for all the info! I'll do some tests.

Olivier
User Avatar
Member
92 posts
Joined: Aug. 2010
Offline
In production, we get open surfaces from Modeling often. The common practice is to convert the mesh to an unsigned distance field prior to converting to a signed distance field.


I have an example in the Houdini example file https://www.openvdb.org/download/ [www.openvdb.org] Look for /obj/example_levelset/extruded_sdf
Edited by jbudsberg - April 10, 2024 13:02:11

Attachments:
tmp.jpg (67.3 KB)

  • Quick Links