Procedural, Parametric. Differences?

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So my understanding is that “procedural” points to functions and “parametric” to parameters.
But parameters of what? Of a function right?

Take modeling, what's the difference between parametric modeling and procedural modeling?

It's a context thing? CAD Modeling is often called parametrix. In Houdinig I think people would call modeling procedural.

Dunno.

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Procedural guy says: I design a procedure which produces for me the result I want. Once procedure is created, I can repeat its run effortlessly or change some part of it, to get different result easily.

Parametric guy says: I create using parametrized stuff, that is I use measurable characteristics (parameters) to create something more complicated than parameters them self (like just a few numbers describing endlessly smooth NURBS surface). This way I use less space and time to create more advanced stuff.

Procedural creation be parametrized or not, and vice versa.
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Procedural and Parametric are two word that usually useful with together in the Houdini.

Peocedural means you have all of the history of your project from start to end with a nodes.

for example in the Modeling , you have a Box node , then this node connected to some different modeling nodes such as Extrude , Bevel , UV , … , and after them you have final model (e.g car).

Now in the Procedural workflow you can change any of these steps every time that you like , for example changing UV , or increasing Bevel or etc.

So you can create another models just with different changes on this network .

in non-procedural softwares , you just have your last model , after finishing your final model , you can't change your source model or change Bevel parameters from previous steps.

One of the great features in the Procedural system is some of the data are shared in different steps , So your file size is very smaller than others , and it's so faster than others too !


Because in this case just networks of this model will save to the file , not all of the data (such as vertices) of the final model.



in Parametric word (in Houdini) , we can export some of important parameters from different nodes to the final node , then users can change final result with changing these parameters. Parametric is usually useful in HDAs
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I think this is a simple example of Procedural System.
in this example you can change input geometry (without any problem) , then all of the operations after this step will apply correctly :idea:

Attachments:
JK_Procedural System.hip (96.6 KB)

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I would think Parametric depends only on parameters while procedural depends on inputs as well. Then again one of those parameters could be an input, so…
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One way to think about Proceduralism is to define what makes something NOT procedural. For modelling it would be where you extrude some edges based on if they are open edges (procedural) rather than extruding edge 10 and edges 34-45 explicitly (non-procedural).
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I guess that procedural is based on a “procedure” kind of step by step work-flow
Parametric instead is based on parameter without a real “start to end” flow

the difference is subtle; let's say that if you have to design a real object, rely on parameter is better ( see also grasshopper 3d or revit)
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Maybe Procedural and Parametric should be used with each other ,Because If you do a procedural things (witch means you have all your operation step by steps) in the Houdini ,Then you can promote some important parameters from this procedural network for doing some changes in final result
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Briefly:
Procedural is about retirement of famous CTRL + Z.
Parametric is about giving various inputs and getting instant outputs.
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To me “procedural” is the more suitable term, because parameters are just an element of a procedure. The results of procedures vary if you change values of certain parameters. The terms procedural and parametric are often used interchangeably, though.
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Yeah I thought about it yesterday again and I think this is it x)

Procedural: Logic stack of operations, which is thought out as code, meaning you make it responsive to many cases. That's why even selections might be inferred and not picked in the viewport.

Parametric: Exposed Inputs (meshes, variables) that allow you to drive the operations.
Edited by probiner - Oct. 26, 2017 09:28:31
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Here is an analogy for proceduralism. Instead of cooking food, you are writing recipes. Once you have the recipe, you can tweak the ingredients to alter the outcome.
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