MASH ID Node: "Probability Ramp" (Maya 2018.4)



The documentation says that you can use something called a Probability Ramp with the MASH ID Node.

"Random: Each object gets a random ID. You can adjust the probability of certain IDs of certain IDs showing up over other IDs using the Probability Ramp. "

I can’t find any Probability Ramp or a slot to connect such a ramp. I understand the principle as I have done something similar with Particles.
Where is this Probability Ramp? Is it within the ID Node Attribute Editor?

Here is a link to the DOCS for the MASH ID NODE.

Thank you.


You can forget about it, it’s not implemented.

Ian started to work on it but wasn’t finished, and now he is not working on MASH anymore.

So the only thing to do is to report it, and ask for it.


Wow. Are you serious? I have learned to trust you cause you are very knowledgeable and informed. But with Maya things are getting more and more unbelievable every day. MASH has turned out to be more of a disorganized disaster than MAYA ever was. And that alone is very hard to believe. A tornado in Arkansas leaves things more organized than MAYA after it passes through. But I guess that is what happens to anything that Autodesk (MAYA) licenses/purchases, and tosses into the main package and then forgets.

What’s worse?

Missing documentation for existing features?
Missing features described in existing documentation?
Existing features that do not produce the results described in existing documentation?

Yes. Those are the only available options with MAYA. Anything else is an accidental BONUS tool.

Thanks again Onuris.

(What’s up with the new look of CGTalk. This is making me claustrophobic. This is even worse than the previous look. The previous look took me many years to accept. This will take me a lifetime.)


You were right. The feature does not exists but it is “advertised” in the DOCS. Talk about “bait and switch”…

This is the response on the official Autodesk forum:

Re: MASH ID Node: “Probability Ramp” (Maya 2018.4)

I talked to a dev and they said that mention in the docs has been removed and that refreshing your cache for your browser should show the changes.
I'm looking into this more however to make sure it has been removed since obviously that shouldn't be apart of the docs since it is currently not apart of Maya.
All the best,

**Name Removed**
Technical Support Specialist

follow up reply or edit of reply

Update from the dev.
They did remove mention of the Probability Ramp in one part of the docs but the link you shared was missed somehow. That said it's on their radar now thanks to your post and they are working to fix it.


My impression has been that the software (MAYA) is not Beta tested enough prior to release. But now I am seeing that when Autodesk Maya is purchasing/licensing 3rd party tools, they don’t even check if what they are purchasing/licensing is indeed what it is supposed to be. And then they are passing it on “AS-IS” to the users. That’s like buying a car that is not really a functioning car. It just a design of what could be a car. And then re-selling it.


it turns out that the feature described (Probability Ramp) wasn’t even necessary. You can do everything described with the strength map. It would be nice if the docs didn’t have mistakes. The program has enough bugs as it is. So much time wasted sorting out this Autodesk Maya sloppiness.

Sometimes I wonder how many developers work to make Maya today. Is it just ONE and not even full time?


yes you have some ways to somehow fake it, but it’s not ideal.

But actually it’s really a missing feature that was supposed to be here, i remember back in the day long before the Autodesk acquisition(it was still in python i think), i asked Ian if it was possible to add this feature.

So after the acquisition i also saw in the documentation that the feature was there, but wasn’t actually in maya so i dropped a mail to Ian to be sure and he told me that he didn’t finish this feature and that now he is not on the project anymore.

But i still wish that at some point they will add it one day. Something like the probability in Forest pack with percentage.


I got it to work with percentages through an expression.

I still feel like I am wasting my time with Maya… and MASH now…


it makes me think of something, this might be useful to you if you want to have a node based approach
Its a set of math nodes for maya, it’s pretty useful for a lots of things.
It’s an open source project and free, you have a compiled version on the soup site.