I am very new to this package and have run into a situation that I cant figure out.

How can I scale this object (preferably in y) without the squishing or stretching depending of the direction of the transform?

You should provide a hip.

Because scaling will ‘squish/stretch’ any of the geometry that has the scaling applied to it.

So what you want to do is apply scaling selectively. In this case assuming you want to keep the arch? Then just enlarge(scale) the box it lies in only.

But we need a hip, so someone can show you.

From your pic it looks like simply creating a group of points(the outer corner of the box) and use a transform node with the group specified so the scaling only applies to those points.

This is happening in every 3D software not just Houdini !
That's a rule, if you scale everything in one axis, it will deform !
As BabaJ said, you have to consider this in modeling.

Thanks for the replies.

Typically in other 3d packages I would select the top/bottom verts and move or scale out from the center to the desired potions. I am trying to learn procedural modelling approaches for things like this. Are there node combinations or expressions that produce the same results?

For what I mentioned that would be using the group node and transform node. Of course, there's many different approaches to do the same thing.

As before, post a hip if you can't get a solution.

Also better to not try and emulate approaches of other software packages, better to emulate the end result.

That way your in a better position to take advantage of what's available.

You might be interested in a good explanation by Mestela of what appears to be the current context your thinking about;

http://www.tokeru.com/cgwiki/index.php?title=Points_and_Verts_and_Prims [www.tokeru.com]

You could actually try to emulate what you would do in other packages with nodes in Houdini
Imagine each step you'd do manually is a node that does that thing for you.

I guess you would do this ( for non squishy x axis scaling ):
- select one half of the geometry
- move that half along the x axis
- invert the selection
- move the other half in the opposite direction by the same amount

Like BabaJ suggested this can be done with groups and transform nodes.
To invert a group you can add a ! to the name, so !mygroup means “everything except mygroup”
>> https://www.sidefx.com/docs/houdini/model/groups.html [www.sidefx.com]

The other thing are referenced parameters on the transforms, that simply have a minus sign in front the expression.
( You could also use the “invert Transformation” option instead of the minus sign )
>> https://www.sidefx.com/docs/houdini/network/copying.html [www.sidefx.com]

This is just one way to do it and there are so many ways to solve the same problem in Houdini.
Some are faster, some are easier to understand and some perform better, so keep experimenting and playing around. It's a huge sandbox

Here's a quick example and attached Hip file:

blackpixel_mv
You could actually try to emulate what you would do in other packages with nodes in Houdini
Imagine each step you'd do manually is a node that does that thing for you.

I will give this a try. Thanks for the help.