admin – Page 76 – Houdini-and-Chill

Archived post by lcrs

to find the “difference” between your two matrices you can invert the first then multiply by the second – think of it like “remove the transform of matrix1 from matrix2, leaving just the difference between them”. that gives you a matrix, which you can turn into a quaternion, which you can turn into an angle/axis rotation like @w “`matrix3 m1 = ident(); matrix3 m2 = ident(); rotate(m2, 0.5, {1, 0, 0});
matrix3 diff = invert(m1) * m2; vector4 quat = quaternion(diff); v@w = qconvert(quat);“`

Archived post by JeffLMnT

Oh… A cool way to mask disturbance based on velocity is to set the control field to vel… And Crack open the disturbance microsolver>disturb field gas vop and the adding a length vop after the control field parm.

Another fx artist at work pointed this out to me

Saved the 5 mins to takes me to build a speed field

Archived post by will

@mstarktv

what a cool way to do curve sag:) thanks for the idea

i used to do a three point curve, move the middle point (point 1) down with a transform, and then do a convert to nurbs and resample. This however has a lot fewer steps

funnnn

the hip file if someone wants it

Attachments in this post:
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20183709/10/18/unknown.png
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20183709/10/18/curveu_fun.mov
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20183709/10/18/curveu.hiplc

Archived post by lcrs

used stuff like this a lot to do grassy fields and tbh we didn’t always have it generate the geo inside mantra, you can switch the hairgen to just creating standard SOPs geo. obvi the IFDs got massive that way, but if you’re rendering from Indie direct to mantra i’m not sure there’s much speed or memory improvement having it generate inside mantra vs. baked inside H and then streaming the geo to mantra… 100 curves with 300k render-time hairs here streamable.com/m6km2

Attachments in this post:
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20185309/07/18/Ls_hairgen_from_lines_v02.hiplc

Archived post by jake rice

yeah 😦 i could potentially have a catch for that

😮

secccc

“`c //this still goes in a prim wrangle void select_border_diff(string current_group; int primnum){ int in_curr = inprimgroup(0, current_group, primnum); if(!in_curr) return; int h = primhedge(0, primnum); int temp = h; do{ int nb_prim = hedge_prim(0, hedge_nextequiv(0, h)); if(!inprimgroup(0, current_group, nb_prim)) setedgegroup(0, “border”, hedge_srcpoint(0, h), hedge_dstpoint(0, h), 1); h = hedge_next(0, h); }while(h != temp); } string a = chs(“group_a”); int in_a = inprimgroup(0, a, @primnum); select_border_diff(a, @primnum); “` this one selects only the border of a single given group

which is what i shouldve done in the first place but 🤷