topic Re: #paramBlock2 scripted plugin parameter type. How to use? in 3ds Max Programming Forum

#paramBlock2 scripted plugin parameter type. How to use?

AndyVanDalsem — Thu, 04 Jun 2026 17:14:05 GMT

Hi guys,
I have maybe a stupid question but I can't find any examples anywhere.

In the help docs for scripted plugins clauses, it says available since 2018 there's a parameter type called #paramBlock2.

parameters main rollout:params ( size type:#worldUnits ui:size default:150 paramTest type:#paramBlock2 -- <-- How do I use this? )

But I can't really see how to use it. Can anyone point to some example usages that I could look at?

In the code above for example, now that there's a parameter `paramTest`, how do I populate it? Do I assign it an instance of another object's params?

In that case, I'm not even sure how to easily/safely access another objects paramBlock. You have this way:

<void>paramPublishMgr.addParameterBySubNum <maxObject>paramParent <index>paramSubnum

But you have to have the obj selected in trackview.

This way can return the paramBlock:

(refs.dependsOn $.baseobject)

But it can return an array of multiple blocks or other nodes and I'm not sure how to filter just the params, or even how to figure out which params are the ones I'm looking for.

But, say I could isolate the params, would I assign them to my #paramBlock2 item type like this?
$obj_A.paramTest = $obj_B.params?

Or can I define the params in a variable somewhere and assign it that way?

storedParams = parameters stored ( range type:#float default:25.5 )

$obj_A.paramTest = storedParams

Can paramTest's populated block then be linked to UI elements?

Anyway, thanks for any examples or links to documentation.

Re: #paramBlock2 scripted plugin parameter type. How to use?

denisT.MaxDoctor — Fri, 05 Jun 2026 00:31:02 GMT

for example, cust attributes have paramblock2s

global CAPB2 = attributes CAPB2 attribid:#(0x00de01, 0xde00de) ( parameters params ( power type:#float default:1.0 on power set val do ( format "power set >> %\n" val ) ) ) ca = createinstance CAPB2 ca.power getproperty ca #power ca.power = 0.5 setproperty ca #power 0.25 pb2 = refs.getreference ca 1 classof pb2 getpropnames pb2

Re: #paramBlock2 scripted plugin parameter type. How to use?

denisT.MaxDoctor — Fri, 05 Jun 2026 00:40:10 GMT

another example - a built-in modifier

( m = Bend() for k=1 to refs.getNumRefs m do format "index:% ref:%\n" k (refs.getreference m k) )

Re: #paramBlock2 scripted plugin parameter type. How to use?

AndyVanDalsem — Fri, 05 Jun 2026 01:19:40 GMT

This is great, thank you. Exactly what I needed.

Re: #paramBlock2 scripted plugin parameter type. How to use?

larryminton — Fri, 05 Jun 2026 13:51:52 GMT

To a large extent #paramBlock2 and #paramBlock2tab aren't that applicable to maxscript, and are more for c++ sdk completeness and testing.

In the c++ world #paramBlock2tab is used for things like the Conform modifier and the Boolean modifier to store information on each operand.

To be similarly applicable in maxscript, would need a way to specify for each 'parameters' block whether it should not be automatically created when the plugin instance is created, and a way to create it so that it could then be assigned/added to the #paramBlock2/#paramBlock2tab parameter.

Re: #paramBlock2 scripted plugin parameter type. How to use?

AndyVanDalsem — Fri, 05 Jun 2026 15:54:46 GMT

Ah, ok. I think I understand.

That's kind of what I was thinking about doing with it was storing operand-type data in the #paramBlock2 parameter. I didn't even know there was a #paramBlock2tab type! It's not shown anywhere in the Maxscript docs that I could find.

I'm going to play around with it just because I'm curious, but it's good to know it's more of a c++ thing.

Thanks for the info!

Re: #paramBlock2 scripted plugin parameter type. How to use?

larryminton — Fri, 05 Jun 2026 16:00:59 GMT

fixing doc...

|`#paramBlock2Tab`|available since 3ds Max 2018|

|`#point2Tab`|available since 3ds Max 2018|