Old tutorial New Houdini Hiccup

[Gilly123]

First off, new here, HELLO, so I signed up over at Digital Tutors for another app (Zbrush) and then realized I get everything, so I immediately have been bitten by the Houdini bug.

 

That said, Ive done a handful of the tutorials and Im dealing with old tutorials on the new H15. I've managed to work my way thru previous ones, but this one has me STYMIED!.

 

The project is on using the L-Systems. And where it has proven a problem is where using an attribute create. Once I enter a name, in this case "width", the data dissapears and you get the SOP has not cooked correctly error.

 

Since it was breaking everything down the line, I branched it off to see if I could isolate it and then proceed with the tutorial. Well now it's at the point where we are done building the TREES and about to move on. I'd hate to give up on this just because I should be using another node that was a click away. And since Im new to it all, I dont want to have giving up part of the new learning curve.

 

If Digital Tutors is not the best, who is for Houdini training? I like how the tutorials have been. I joined up based on learning zbrush.

 

Any help would be appreciated, I will upload the file.

 

Gilly

L_Systems_Trees.hipnc

[magneto]

Are you talking about using the variable $WIDTH?

[Gilly123]

Yes, that is what falls apart once I enter "width" in the name descriptor. It's supposed to be part of determining the circumference of the tree from bottom to top and the expression inside the node is supposed to thin it out as the tree grows.

 

EDIT: I should have been more precise in my description on which node was giving me issues.

 

attrib_WIDTH, the Name descriptor. Once "width" is entered in the Name, all data drops out.

 

 

 

Apologies for the above.

 

Gilly

Edited December 31, 2015 by Gilly123

[magneto]

I am not in front of Houdini but you can create a variable using AttribCreate or addvariablename VEX function.

[Gilly123]

Trying to find this VEX function to do the addvariablename, not having much luck.

[bonsak]

It's here:

http://www.sidefx.com/docs/houdini15.0/vex/functions/addvariablename

 

-b

[mawi]

First off, new here, HELLO, so I signed up over at Digital Tutors for another app (Zbrush) and then realized I get everything, so I immediately have been bitten by the Houdini bug.

 

That said, Ive done a handful of the tutorials and Im dealing with old tutorials on the new H15. I've managed to work my way thru previous ones, but this one has me STYMIED!.

 

The project is on using the L-Systems. And where it has proven a problem is where using an attribute create. Once I enter a name, in this case "width", the data dissapears and you get the SOP has not cooked correctly error.

 

Since it was breaking everything down the line, I branched it off to see if I could isolate it and then proceed with the tutorial. Well now it's at the point where we are done building the TREES and about to move on. I'd hate to give up on this just because I should be using another node that was a click away. And since Im new to it all, I dont want to have giving up part of the new learning curve.

 

If Digital Tutors is not the best, who is for Houdini training? I like how the tutorials have been. I joined up based on learning zbrush.

 

Any help would be appreciated, I will upload the file.

 

Gilly

 

Hey.

If you middleclick on a node it will tell you why it errors out.

In your case you are trying to use a $ARCMAX variable in a expression in the attrib_WIDTH node.

$ARCMAX doesn´t exist and the node errors with the message "undefined variable".

Also you need to keep an eye on what class a attribute is set to. In your attrib_width node it comes in as point float, but you are trying to use it a s a primitive vector.

 

Wrote some notes, but let me know if this didnt solve your problem.

L_Systems_Trees-3.hipnc

[Gilly123]

Thanks Illusionist, that was helpful.

It is so easy to forget a small thing that ends up doing or not doing something down the line, which is sort of what makes figuring it out part of the fun/challenge.

 

I don't have the math background that comes into play, but as with all things, if you practice and use the math language enough, it will rub off!

 

I'm still quite amazed at how the end result is to reverse engineer a visual effect in a sense using what Houdini offers as your tool set to build a node system that produces the look or action desired in the first place. They should use  Houdini in school to teach math and to reach more people earlier in life. Seeing math do things is what lacks in typical high school classes.

 

Thanks again for helping me out. I do try to refrain from posting every time I hit a bump where something goes wrong. And while the project files are there to load, I want my version to work since that is the point of it all.