Hi guys, is it just me or does everybody have difficulties understanding the lattice SOPand how to get it working.

From the manual

Connect the source geometry (the geometry to deform) to the first input, the rest geometry (the initial shape of the control geometry) to the second input, and the edited form of the control geometry to the third input (this is usually one or more Transform SOP s, although you can use any editing nodes. You can also use the Edit SOP , although it can't be animated).

The first part I get , create a simple tube wire it into the first input on the lattice SOP. The second part I dont quite get “rest geometry ”. The example shows a bound SOP plugged into the second input why ? surely the cylinder is at rest as Ive not done anything to it, whats the reason for having this second slot that needs an extra node being the bound sop ? surely it would make better sense to have the entire lattice / bound SOP combined into one SOP. I understand I plug the edit SOP in the 3rd slot , but why not have a lattice sop plug into the edit SOP , creating a simple chain of operators.

In the mean time I created the nodes shown in th manual. Using the edit SOP I select some points on the lattice (s) , right click nothing happens , I then hit return and I get the global transform tool come up ,with nothing selected, I move it around and the values inside the edit SOP transofrm tab alter so I am inside the edit sop. Needless something like applying a lattice should not be this difficult it isnt in any other application! i
So any advice on the why the lattice sop is set up this way would be helpfull. Also how I am suppossed to get it working lol ….. the examples really dont help ….



R

Hi,

The rest geometry (second input) is needed so the Lattice SOP knows what is different from the control geometry (third input) then deforms the source geometry (first input) based on the difference.

When you were transforming the handle of the Edit SOP, did you check to make sure it wasn't connected to the second input?

For an example, there is a 3D Buzz video, Houdini Issue 1 video 6 (Title: Creating Networks) which shows how to use the Lattice SOP.

Cheers!
steven

hey steven thanks for the tutorial tip , ive just had a look at it and still , after he selects the points right click , he gets a transform icon , I try to right click and get nothing …..I have found on some operators I get results if I add the operator via the view instead of just creating an operator in the network editor and wiring it up…its got me baffled ! , in fact Ive just being some tests ..

Select the geo ie a teapot in the viewport ( S key ), then I select points , select the whole teapots points.While in viewport I tab and add an edit SOP and what do you know the edit sop works.When I select points right click I get a transform icon. try creating and adding an edit sop in the network editor and what do you know it wont work , you select the points , right click and nothing …..
I must be doing something fundementally wrong , ive even changed my mouse !

R

Never the less Im getting some good results out and I now have a teapot behaving like a large lump of jelly ! I will post up a scene at some point who knows it might help others all in name of discovering how to do a candle flame !

I have a softbodydeforming a latice it works great but obviously looks like jelly.
In the group POP I noticed from the various examples you can define a rules for POPS so why not to control the effect of a force on a particles position.
How would I go about defining a rule that would apply a greater force the higher the particles are in Y on my lattice , so when more force is applied the lattice would move more at the top and less at the bottom.

R

Hi,

In the Force POP, you can put the following into the X & Z parameters:
fit($TY, 0, 10, 0.1, 5) * 30

Points that are at 0 in Y gets a value of 3 while points at 10 in Y gets a value of 150.

You can also use $BBY which is the Y-axis bounding box.

Hope the above helps!

Cheers!
steven

Thanks for the help steven.