Houdini-and-Chill

`// formula to change from one space to another // P = inverse(m1) * m2
// get the position and orient data vector start_p = point(0, “P”, 1); vector end_p = point(0, “P”, 2); vector4 start_orient = point(0, “orient”, 1); vector4 end_orient = point(0, “orient”, 2);
// calculate the blended values float blend = fit(@Frame, 1, 48, 0, 1); end_p = lerp(start_p, end_p, blend); end_orient = slerp(start_orient, end_orient, blend);
// matrix at start matrix3 start_m = qconvert(start_orient); vector start_n = set(start_m.zx, start_m.zy, start_m.zz); vector start_up = set(start_m.yx, start_m.yy, start_m.yz); matrix a = maketransform(start_n, start_up, start_p);
// matrix at end matrix3 end_m = qconvert(end_orient); vector end_n = set(end_m.zx, end_m.zy, end_m.zz); vector end_up = set(end_m.yx, end_m.yy, end_m.yz); matrix b = maketransform(end_n, end_up, end_p);
matrix final = invert(a) * b; pos = pos * final;`

There we go! Thanks so much! @TOADSTORM + @jake rice 😮 . Infinite fishies for me!

Need to handle scale, but I already have code for that.

In case you want to speed up the Point Deform SOP ( a lot ), you can disable the xformbyattrib1 node inside the hda. That is in charge of deforming custom attributes. Should really be disabled by default and there should be a checkbox to enable it on demand. We’re talking about ~x5 speed improvement. If you disable the ‘attribdelete1’ node as well, you’ll gain another ~10% in speed.

so, timeshifts and for loops

kindasorta got a definitive answer

“The For Each Begin SOP does not do an implicit blast on it’s input unlike the Each SOP that was there in previous releases. If you put a Time Shift SOP before the Fetch, it will seem like it is not working as the Fetch isn’t cooking it’s input. It will return the same piece of geometry for all time. To correct this, use a Blast SOP and delete out the piece you want with detail expressions pointing to a Meta Data SOP.” – Jeff Lait

More explicitly, don’t let the begin block split your geo for you. Change it to ‘fetch input’, so it brings in everything on each run of the loop, then manually isolate to the thing you want, by using info from the metadata sop. Now any timeshifts within the loop will behave.

a gif to explain that: www.tokeru.com/cgwiki/images/5/55/Forloop_timeshift_fix.gif

the bend deformer uses it i believe

but i’ll post up an example

notice how with the deformation wrangle, i use `pos` instead of `@P` for all references to position. this is necessary for it to do it’s magic

you can use `@P` in deformation wrangles, but just know that the attribute update magic won’t work if you do it

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http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20194607/16/19/jr_deformation_wrangle_example.hip