Hi,
Sorry for the lame question, but how do I access attributes in the Attrib Wrangler SOP from anything than the 1st input?
cheers
Attrib Wrangle inputs
34711 16 5- riviera
- Member
- 1705 posts
- Joined: March 2020
- Offline
Imre Tuske
FX Supervisor | Senior FXTD @ Weta FX
qLib -- Houdini asset library
http://qlab.github.io/qLib/ [qlab.github.io]
https://www.facebook.com/qLibHoudini [www.facebook.com]
FX Supervisor | Senior FXTD @ Weta FX
qLib -- Houdini asset library
http://qlab.github.io/qLib/ [qlab.github.io]
https://www.facebook.com/qLibHoudini [www.facebook.com]
- old_school
- Staff
- 2540 posts
- Joined: July 2005
- Offline
You can use a function to pull what you want out of the inputs. Have a look at the Wave tank object_fluid1 object. It does this:
// Copy attributes from particles to surface
int handle;
handle = pcopen(@OpInput2, “P”, @P, 1000, 1);
@v = pcfilter(handle, “v”);
// @Cd = pcfilter(handle, “Cd”);
pcclose(handle);
// Copy attributes from particles to surface
int handle;
handle = pcopen(@OpInput2, “P”, @P, 1000, 1);
@v = pcfilter(handle, “v”);
// @Cd = pcfilter(handle, “Cd”);
pcclose(handle);
There's at least one school like the old school!
- riviera
- Member
- 1705 posts
- Joined: March 2020
- Offline
Thanks for the info – although I was afraid of the answer is going to be something like this (my guess was getattribute(), though ).
If you allow me some criticism (intended to be constructive), the problem with this is that although this solution works for particular cases, it's not as elegant as the ‘@’ notation that seems to be preserved for the 1st input only.
The elegance of the ‘@’ notation is that you don't have to know what class you're working with (point, primitive, vertex, detail), and your code will still be the same.
You think I could ask an RFE for this? A shorthand syntax for the other inputs would make the wrangle node(s) even more powerful. (Though I'm aware this would make sense only if all input geometry had the same topology… probably there's other related issues to think about here, too… hm hmm…)
Anyhow, let's say I'm just thinking out loud about having an unified syntax for those non-primary inputs… In the meantime I'll dig into those fluid OPs, perhaps I'll find some other tricks of the trade in the wrangle business Thanks for the help!
Cheers
If you allow me some criticism (intended to be constructive), the problem with this is that although this solution works for particular cases, it's not as elegant as the ‘@’ notation that seems to be preserved for the 1st input only.
The elegance of the ‘@’ notation is that you don't have to know what class you're working with (point, primitive, vertex, detail), and your code will still be the same.
You think I could ask an RFE for this? A shorthand syntax for the other inputs would make the wrangle node(s) even more powerful. (Though I'm aware this would make sense only if all input geometry had the same topology… probably there's other related issues to think about here, too… hm hmm…)
Anyhow, let's say I'm just thinking out loud about having an unified syntax for those non-primary inputs… In the meantime I'll dig into those fluid OPs, perhaps I'll find some other tricks of the trade in the wrangle business Thanks for the help!
Cheers
Imre Tuske
FX Supervisor | Senior FXTD @ Weta FX
qLib -- Houdini asset library
http://qlab.github.io/qLib/ [qlab.github.io]
https://www.facebook.com/qLibHoudini [www.facebook.com]
FX Supervisor | Senior FXTD @ Weta FX
qLib -- Houdini asset library
http://qlab.github.io/qLib/ [qlab.github.io]
https://www.facebook.com/qLibHoudini [www.facebook.com]
- animatrix_
- Member
- 4683 posts
- Joined: Feb. 2012
- Offline
If there will be a new syntax, here is an idea:
@Cd(2)
To get the Cd attribute from the second input.
@attribute(inputNumber)
if left out, then it's implicitly the first input just like now.
I thought I would post this if people were looking for some syntax ideas.
@Cd(2)
To get the Cd attribute from the second input.
@attribute(inputNumber)
if left out, then it's implicitly the first input just like now.
I thought I would post this if people were looking for some syntax ideas.
Senior FX TD @ Industrial Light & Magic
Get to the NEXT level in Houdini & VEX with Pragmatic VEX! [www.pragmatic-vfx.com]
youtube.com/@pragmaticvfx | patreon.com/animatrix | pragmaticvfx.gumroad.com
Get to the NEXT level in Houdini & VEX with Pragmatic VEX! [www.pragmatic-vfx.com]
youtube.com/@pragmaticvfx | patreon.com/animatrix | pragmaticvfx.gumroad.com
- tjeeds
- Member
- 339 posts
- Joined: Aug. 2007
- Offline
- riviera
- Member
- 1705 posts
- Joined: March 2020
- Offline
Previously I had troubles with getattribute() in an AttribWrangler SOP, but after giving it the good ol' time-and-patience combo, it seems to be working for me. Examples:
Getting the Cd attribute from second input (point class):
getattribute(@OpInput2, @Cd, “point”, “Cd”, @ptnum, @vtxnum);
Same but for primitive class:
getattribute(@OpInput2, @Cd, “primitive”, “Cd”, @primnum, @vtxnum)
Add some hscript-expressions as syntactic pepper, and you have a line that works for both points and primitives:
getattribute(@OpInput2, @Cd, “`chs(”class“)`”, “Cd”, @`ifs(!strcmp(chs(“class”),“point”),“pt”,“prim”)`num, @vtxnum);
My apologies for the last one – but it truly works! Although I doubt anyone would want to conjure that up each time a class-independent getattribute is needed.
My vote goes for @Cd(2) instead…
Getting the Cd attribute from second input (point class):
getattribute(@OpInput2, @Cd, “point”, “Cd”, @ptnum, @vtxnum);
Same but for primitive class:
getattribute(@OpInput2, @Cd, “primitive”, “Cd”, @primnum, @vtxnum)
Add some hscript-expressions as syntactic pepper, and you have a line that works for both points and primitives:
getattribute(@OpInput2, @Cd, “`chs(”class“)`”, “Cd”, @`ifs(!strcmp(chs(“class”),“point”),“pt”,“prim”)`num, @vtxnum);
My apologies for the last one – but it truly works! Although I doubt anyone would want to conjure that up each time a class-independent getattribute is needed.
My vote goes for @Cd(2) instead…
Imre Tuske
FX Supervisor | Senior FXTD @ Weta FX
qLib -- Houdini asset library
http://qlab.github.io/qLib/ [qlab.github.io]
https://www.facebook.com/qLibHoudini [www.facebook.com]
FX Supervisor | Senior FXTD @ Weta FX
qLib -- Houdini asset library
http://qlab.github.io/qLib/ [qlab.github.io]
https://www.facebook.com/qLibHoudini [www.facebook.com]
- henderthing
- Member
- 7 posts
- Joined:
- Offline
- zachlewis
- Member
- 45 posts
- Joined: March 2010
- Offline
riviera
Add some hscript-expressions as syntactic pepper, and you have a line that works for both points and primitives:
getattribute(@OpInput2, @Cd, “`chs(”class“)`”, “Cd”, @`ifs(!strcmp(chs(“class”),“point”),“pt”,“prim”)`num, @vtxnum);
Heh - that's pretty clever.
In general, does evaluating HScript within a wrangle node like that slow things down? Or is the HScript evaluated before the VEX gets compiled? And how the hell does that work if you have backticked HScript within a VEX loop, or something?
- old_school
- Staff
- 2540 posts
- Joined: July 2005
- Offline
zachlewisriviera
In general, does evaluating HScript within a wrangle node like that slow things down? Or is the HScript evaluated before the VEX gets compiled? And how the hell does that work if you have backticked HScript within a VEX loop, or something?
Gets evaluated when the vex is compiled.
You can see exactly what is happening if you dive inside the asset and RMB on the VOP SOP and choose: View VEX Code…
In the View Code dialog, your code passed in to the Snippet VOP (which is actually supplying the UI at the top) is declared as a void expression with a unique name to the path to this VOP.
As you can see the hscript has already evaluated and constructed the correct result in this void function.
There's at least one school like the old school!
- circusmonkey
- Member
- 2624 posts
- Joined: Aug. 2006
- Offline
- tamte
- Member
- 8773 posts
- Joined: July 2007
- Offline
match by attribute will find the point in second input whose attribute value matches that attribute value of current point of first input
so if your matching attribute is id then basically this
int matching_pt = findattribval(@OpInput2, “point”, “id”, @id);
now you can import any attribute from that matching point of second input and you should have the same result as with Point SOP
so if your matching attribute is id then basically this
int matching_pt = findattribval(@OpInput2, “point”, “id”, @id);
now you can import any attribute from that matching point of second input and you should have the same result as with Point SOP
Tomas Slancik
FX Supervisor
Method Studios, NY
FX Supervisor
Method Studios, NY
- circusmonkey
- Member
- 2624 posts
- Joined: Aug. 2006
- Offline
Thanks ,
I have been trying to get my next part running without success
// turn on point matching and look at the 2nd inputs id attribute
int matching_pt = findattribval(@OpInput2, “point”, “id”, @id);
// Then in point sop workflow I would add $TX2 , $TY2 , $TZ2 . I thought ok so as we are using point matching now id will be used instead of the default ptnum in the second input I would add
@P = point(@OpInput2, “P” , @id);
Thinking P will now get its value from the 2nd inputs “P” and match to Id . But something is not correct with my vex !
Rob
I have been trying to get my next part running without success
// turn on point matching and look at the 2nd inputs id attribute
int matching_pt = findattribval(@OpInput2, “point”, “id”, @id);
// Then in point sop workflow I would add $TX2 , $TY2 , $TZ2 . I thought ok so as we are using point matching now id will be used instead of the default ptnum in the second input I would add
@P = point(@OpInput2, “P” , @id);
Thinking P will now get its value from the 2nd inputs “P” and match to Id . But something is not correct with my vex !
Rob
Gone fishing
- tamte
- Member
- 8773 posts
- Joined: July 2007
- Offline
- circusmonkey
- Member
- 2624 posts
- Joined: Aug. 2006
- Offline
Thanks Tomas ! , so much to learn with vex , keeping in tune with the attribute line of questions
v@position_real = @P;
addvariablename(“pos_real”,“POS_REAL”);
The above returns in the details view pos_realpos_realpos_real If I declared the attribute as a vector surely is should be pos_realpos_realpos_real . As when using a attribute create sop set to vector with values $TX,$TY,$TZ .
Rob
v@position_real = @P;
addvariablename(“pos_real”,“POS_REAL”);
The above returns in the details view pos_realpos_realpos_real If I declared the attribute as a vector surely is should be pos_realpos_realpos_real . As when using a attribute create sop set to vector with values $TX,$TY,$TZ .
Rob
Gone fishing
- tamte
- Member
- 8773 posts
- Joined: July 2007
- Offline
- Alejandro Echeverry
- Member
- 691 posts
- Joined: June 2006
- Offline
tamte
match by attribute will find the point in second input whose attribute value matches that attribute value of current point of first input
so if your matching attribute is id then basically this
int matching_pt = findattribval(@OpInput2, “point”, “id”, @id);
now you can import any attribute from that matching point of second input and you should have the same result as with Point SOP
:shock: Thank you Tomas!!!
Feel The Knowledge, Kiss The Goat!!!
http://www.linkedin.com/in/alejandroecheverry [linkedin.com]
http://vimeo.com/lordpazuzu/videos [vimeo.com]
http://www.linkedin.com/in/alejandroecheverry [linkedin.com]
http://vimeo.com/lordpazuzu/videos [vimeo.com]
- circusmonkey
- Member
- 2624 posts
- Joined: Aug. 2006
- Offline
-
- Quick Links