Maya 2020 fundamentals - modelling the real world
Get halfway through a model and find it's an unworkable mess? Can't add edge loops where you need them? Can't subdivide a mesh properly? If any of this sounds familiar check this course out.
# 1 06-01-2003 , 10:40 PM
NitroLiq's Avatar
Moderator
Join Date: Nov 2002
Location: New York
Posts: 2,133

Need help troubleshooting expression.

I'm playing around with different approaches to simulating seas and whatnot and have been perusing this tutorial. Everything is apparently setup correctly in my scene but I keep getting an error when using their expression. Here are the steps if you want to try and recreate it real quick:

1. Create a horizontal square cubic NURBS plane of width 100 units and divided into 50 spans in both u and v directions.

2. Make the plane a soft body (creation options: make soft). Rename this particle shape node (not the transform node) to seaparticle.

3. Open the attribute editor on seaparticle. Go to the section called Per Particle (Array) Attributes, RMB-press the position field, and choose Runtime Expression from the pop-up menu. Input the following expression:

Code:
vector $dummy1 = seaparticle.position0;
vector $dummy2 = <<$dummy1.x/6 + 59 - frame/20, 27 + frame/40, $dummy1.z/20 + 32>>;
seaparticle.position = <<$dummy1.x, 2.4 * noise($dummy2), $dummy1.z>>;
This should result in a stormy seas-styled billowing like KB's been working on. His method works great but I'm interested in seeing why I can't get the expression to work.

When I go to adjust Per Particle (Array) Attributes for seaparticle, all the fields are grayed out. Even still, I can RMB and open the expression editor in position but keep getting the following error when I create:

"Error: Attribute not found or variable missing '$': seaparticle.position0"

Anyone know what's happening here?


"Terminat Bora Diem, Terminal Auctor opus."
# 2 07-01-2003 , 12:13 AM
kbrown's Avatar
Moderator
Join Date: Sep 2002
Location: London, UK
Posts: 3,198
This is just a wild guess (can't test atm) but you might need to add the position0 attribute to the seaparticle. Open up the attribute editor for seaparticle and under the per particle array section there is a add dynamic attributes or something like that. Anyway, hit the button that says General and from the particles tab choose position0 (or was it pos0)... Again this came from my very tired memory... I'm off to sleep now user added image


Kari
- My Website
- My IMDB

Do a lot, Fail a lot and Learn a lot!
# 3 07-01-2003 , 12:45 AM
NitroLiq's Avatar
Moderator
Join Date: Nov 2002
Location: New York
Posts: 2,133
It's funny I had actually thought of that at the time but didn't try it. I just did the whole thing from scratch again and it worked fine. I wonder if It was misreading the expression before.


"Terminat Bora Diem, Terminal Auctor opus."
# 4 08-01-2003 , 11:05 AM
kbrown's Avatar
Moderator
Join Date: Sep 2002
Location: London, UK
Posts: 3,198
Ignore my previous post. It's BS user added image

Nitro: My guess is that you accidentally made a creation expression while it should have been a runtime expression... or something... user added image


Kari
- My Website
- My IMDB

Do a lot, Fail a lot and Learn a lot!
# 5 08-01-2003 , 01:32 PM
NitroLiq's Avatar
Moderator
Join Date: Nov 2002
Location: New York
Posts: 2,133
KB: Nope, it was runtime. I doublechecked everything. Anyway, I went back and re-did everything with the same settings from worked fine. Last night, I was working on setting up a shader network for the wave texture as well as the seaspray particles but am going to have to re-do at some point....didn't turn out right. For now, though, I think I'm taking a break getting back into the "Maya Fundamentals" tutorials.


"Terminat Bora Diem, Terminal Auctor opus."
Posting Rules Forum Rules
You may not post new threads | You may not post replies | You may not post attachments | You may not edit your posts | BB code is On | Smilies are On | [IMG] code is On | HTML code is Off

Similar Threads