# David Derwin

davidderwin

VFX Artist

Film/TV

LOCATION
United States

Not Specified

## Recent Forum Posts

#### VDB remove interior2019年10月4日17:32

If your polygons are floating on the inside of the mesh and not connected to the outer shell another thing you can try is to convert VDB to polygons just once then plug that into the first input of a boolean sop. Leave the second input of the boolean empty. If the polys are floating on the inside that should remove them and leave just the outer mesh. Saw that on a tutorial somewhere, you can throw down test geometry rubber toy then plug it into the first input of a boolean and see what it does to the inside of the mesh.

#### VEX : using FOR wihtout errors but doesn't work2018年10月22日15:10

You're very close! Your condition in the for loop is currently i==stop, meaning the loop will run as long as i==stop returns true. When the loop starts, i=0 which is not equal to stop (in your example stop would be equal to 2 and in all cases would be greater than 0). I guess it technically isn't incorrect code is why it doesn't error out but it doesn't run as expected.

If you change your for condition to:

```for(int i=0; i<stop; i++)
```

it will work as expected.

Full code only changing that one line:

```int stop = @numprim;

for(int i=0; i<stop; i++)
{
vector pos = prim(0, "P", i);
push(f[]@zpos, pos.z);
}
```

#### edges from knife tool2018年7月2日15:55

One way to do this would be:

1. make a group of all points
2. do knife operation
3. do a group combine set to group type “Points” to make a new point group, set to “Equals All But” the point group prior to knife (from step 1) (this will give you a point group with only the new points created from the knife operation).
4. do a group promote from points to edges on the group from step 3 (making sure to turn ON the toggle to “Include Only Elements Entirely Contained in Original Group”).

This will give you an edge group with just the newly created edge from the knife.

If you have a lot of knife operations and need separate groups for each new knife edge this might not be the most elegant solution but you can repeat the process as many times as needed or can insert as many knife operations after step 2 and get a single edge group from all knife operations.