Category: hou-general

Archived post by rich lord

`// 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.

Archived post by MrWolf

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.

Archived post by mestela

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

Archived post by jake rice

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

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

Archived post by mestela

Archived post by tokyomegaplex

this is not really for you guys as much as it is for people who are asking me how i learned houdini, but i just bought HOUDININERD.COM which links to a google doc i ended up making after enough people asked me to send them resources and stuff. much more convenient than copying the google docs share url every time. if anyone has suggestions for it, more resources or anything else let me know 😛

houdininerd.com

Archived post by jake rice

lemme hook u up with one that works with edits

1 sec

no need for any transformation attributes unless you want to do vector volumes with this technique 😃

this one is all inspired from an old convo in here with tjeeds and matte 😮 😮

you don’t necessarily need to activate a new volume, like you could do this on the original volume, but just know that the bounds will most likely need to be updated to match the deformation tet mesh

Attachments in this post:
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20191504/24/19/jr_non_poopy_vol_deform.hip

Archived post by Bender

you can save them

“Just to expand on the regular presets facility… If you create a bunch of presets for your digital asset, you’ll end up with a file called $HH/presets/Object/myasset.idx, or something similar. This is the file that contains all the preset definitions you have saved. Find this file and remember where it is. Now open the Operator Type Manager and find the definition of your asset. Right-click on it and choose “Edit Contents…”. On the left is a list of “sections” that make up your digital asset definition. Below that list is a spot to enter the name of a file. Use the Plus button to open up a file browser and find the .idx file containing your presets. The “Section Name” will be set to the name of the .idx file. Change the Section Name to “Presets”. Hit the Add File button. Hit Accept. Now those presets are stored with the digital asset.
This ability to store presets directly in a digital asset definition isn’t well advertised because it is far from being an automatic process. Updating that Presets section requires saving it out to the .idx file, adding or editing the presets in that external file, then re-adding the .idx file using the Edit Contents dialog. It’s not pretty, but it can be a very useful feature. “

www.sidefx.com/forum/topic/3449/?page=1#post-254885