[Plugin] SurfaceGen (0.9.0b) — 28 April 2012

[thomthom]

SurfaceGen v0.9 (Beta)

SurfaceGen is a plugin which allows you to create surfaces from mathematical formulae. There are two modes supported:

Function Mode
The Z coordinates of points in a heightmap are specified as a function of X and Y. There can therefore only be one Z value per X, Y coordinate.

Equation Mode
An equation relating X, Y and Z is given. This mode can graph any 3D surface for which there is a formula, but may take slightly longer. The marching cubes algorithm (wow that one is a pain to implement!) is used to generate a surface around a 3D grid of data generated from the equation.

Instructions

- Select the SurfaceGen tool from its toolbar.
- Click to set one corner of the graph.
- Click again to set the opposite corner on the same level.
- Click a third time to set the height of the graph.
- You can transform the resulting group without causing problems.

- After creating the graph and it becoming selected, the SurfaceGen Options window should appear.
- Set the axis ranges, the SurfaceGen mode and enter an equation.
- Choose if you want to show the graph boundary. This will make a semi-transparent box around the graph. The sides facing the camera will always be invisible as you rotate the camera allowing you to see the surface.
- Choose if you want the graph to be smooth.
- Click generate. This may take a few seconds, so be patient. It will happen asynchronously, so you should still be able to move the camera around.
- You can set the surface material by using the paint bucket on the group. The surface will become the selected material.
- Opening the group will cause the graph to turn into a normal group. The plugin will ask if you really want to do this before it actually happens.


Install

Download and extract the attached zip file to your plugins folder. Please remember this is still in beta! I want to hear about any problems you encounter!

Update 0.6
- Updated to work with SketchUp 6

Update 0.7
- Updated to be more compatible with Macs
Now uses built in functions to locate resources and combine paths. Also uses WebDialog.show_modal on macs to get always-on-top behaviour.

- Added more functions
abs, min, max, clamp can now be used in an expression.

- Allowed expressions in axis ranges
You can now easily graph from -pi to pi etc.

- More error checking
You will be notified if an expression is invalid, and hopefully some useful information about why it was invalid will given.

Update 0.7b
- Added point validation to getExtents for the graph tool
The ruby console shouldn't show any errors when drawing a new graph.

Update 0.7c
- Fixed expression parsing bug
Previously, using the same function twice in a row didn't work: sqrt(sqrt(16)) due to the regex used. Now it does.

Update 0.8
- Changed use of pt units to px units in WebDialog
The font should display at the same size in all browsers.

- Now works from any directory
Resources are looked for starting with the directory containing surfacegen.rb.

- Can more easily change WebDialog size
The width as well as the height are constants in surfacegen.rb

Update 0.9
- Increased speed
Previously "eval" was used to evaluate the expression at each sample point, now it uses "eval" once to create a proc object which is called multiple times.

[mitcorb]

Hi, Diggsey:
This looks interesting. You are off to a good start.

[d12dozr]

Diggsey, this is neat! I just started learning this week how to generate implicit surfaces using equations in Meshlab, and I've been importing them into SU - now I can do it all in Sketchup While I don't really understand the math, I just play around with equations and see what pops up.

On that note, do you have any ideas I can use as starters/seed equations for generating neat surfaces? What kind of math would I need to brush up on to understand this stuff better?

For now, I'm just playing, but I have dreams of making some beautiful math sculptures like Bathsheba Grossmanmakes.

Here is a little test I did, using the settings shown in the screenshot.

SurfaceGen.JPG

Did I say thank you, Diggsey?

[d12dozr]

Heh, here's a truncated sphere, settings shown...this is fun!

SurfaceGen2.JPG

Some suggestions:
-When switching to "Equation", change the default settings to something that will work just by pressing "Generate"
-Add a random equation/function generator, perhaps using preset equations
-Add an error message when the equation is invalid, pointing out why its invalid if possible

Like Jean says, just ideas...

[dedmin]

Diggsey, where have You been so far!! We need You! Keep up surprising Us! Thanks!

[d12dozr]

Here's a question for you...is there a way to make the SurfaceGen geometry look like the first Meshlab image? I'm using the same equation, and trying to get results like changing the voxel size in Meshlab, but changing the # of cells in SurfaceGen doesn't seem to have the same effect...am I doing something wrong?

SurfaceGen1.JPG

Meshlab.JPG

Meshlab2.JPG

BTW, I like how the settings are saved for each generated surface!!

[Pilou]

ah very cool!
Topmod and K3dSurf in a same place!
(you can take some formula from K3DSurf

For now, I'm just playing, but I have dreams of making some beautiful math sculptures like Bathsheba Grossmanmakes.

Topmod above is perfect for that
by me

By Jotero

[d12dozr]

Great links, Pilou! Thank you Nice work on the sculpture, too.

[thomthom]

Very nice plugin.

[Pilou]

In the V6 don't works

Error Loading File surfacegen.rb
cannot convert Hash into String

Works fine in the V7

surfacegen00.jpg

[Diggsey]

Thanks everyone who commented!

@d12dozr
I've no idea how to make such complicated structures as those ones you linked to, but you can get some interesting shapes by just mixing up a few of the built in functions:

sin, cos, tan, sinh, cosh, tanh, asin, acos, atan, asinh, acosh, atanh, atan2, hypot, sqrt, cbrt, log, log2, log10, ln, exp

and constants:

e, pi

When switching to "Equation", change the default settings to something that will work just by pressing "Generate"

I'll just make the default equation something that will work for both modes.

Add a random equation/function generator, perhaps using preset equations

That could be interesting. Perhaps the user could choose a level of complexity and it would use that many operations.

Add an error message when the equation is invalid, pointing out why its invalid if possible

Showing an error would be possible, but it might be difficult to point out where. It depends on how much information ruby gives me. For speed, the equation is converted into ruby code, so I can just eval it for each point instead of running my own interpretter.

Here's a question for you...is there a way to make the SurfaceGen geometry look like the first Meshlab image?

I don't know exactly how Meshlab works internally, but it seems like the voxel size is equivalent to the range of values divided by the number of cells. ie:
voxelSize = (max-min)/cells

I'm surprised it should look so different though, just by changing the voxel size.

@Pilou
I've found the problem. It won't let me pass a hash to WebDialog.new.

[thomthom]

@Pilou
I've found the problem. It won't let me pass a hash to WebDialog.new.

Additionally, SU6 only accepts one argument for model.start_operation.

I've used this wrapper:

Code: Select all


def self.start_operation(name)
  model = Sketchup.active_model
  if Sketchup.version.split('.')[0].to_i >= 7
    model.start_operation(name, true)
  else
    model.start_operation(name)
  end
end


The operation will run slower under SU6 - but at least it runs.

[Diggsey]

Thanks thomthom, but I've just used a rescue statement so it will fallback on the older version if the newer one fails. The first post has the updated version which works with v6.

[TIG]

There are also a few error-messages appearing in the Ruby Console that needs traps or begin/rescue forms [e.g. after you explode a special group]...
Some of them relate to your 'recurve' too...
But it's a neat tool

[Diggsey]

I've tried doing everything possible and can't seem to get any output in the ruby console from either plugin. Can you tell me exactly how to reproduce it?

[notareal]

Nice! Can't wait some more complex math sculptures... and naturally even more functionality, like with K3DSurf.

Little test...

[TIG]

I've tried doing everything possible and can't seem to get any output in the ruby console from either plugin. Can you tell me exactly how to reproduce it?

For example...

Error: #<NoMethodError: undefined method `curve' for #<Sketchup::Group:0xa9d06fc>>
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17:in `can_select_curve?'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:32:in `can_select_curve_selection?'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:352

When right clicking a tagged 'surfacegen-group'.
Explode the special surgfacegen-group and right-click gives

Error: #<NoMethodError: undefined method `curve' for #<Sketchup::ComponentInstance:0xb440344>>
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17:in `can_select_curve?'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:32:in `can_select_curve_selection?'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:352
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17:in `call'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17

Erase that 'bounds' Instance then Select the surface...

Error: #<NoMethodError: undefined method `curve' for #<Sketchup::Face:0xad7783c>>
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17:in `can_select_curve?'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:32:in `can_select_curve_selection?'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:352
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17:in `call'
C:/Program Files/Google/Google SketchUp 8/Plugins/recurve.rb:17

These all relate to 'recurve' reaction to 'surfacegen' entities ?
I did have a surgacegen error but I can't get it to reproduce now

[d12dozr]

I've no idea how to make such complicated structures as those ones you linked to, but you can get some interesting shapes by just mixing up a few of the built in functions:

sin, cos, tan, sinh, cosh, tanh, asin, acos, atan, asinh, acosh, atanh, atan2, hypot, sqrt, cbrt, log, log2, log10, ln, exp

and constants:

e, pi

Thank you for this, and considering my suggestions too!

[Pilou]

In the V6
We can draw the "Box" but dialog's window don't opening
No error message, nothing in the Ruby console

[Diggsey]

@notareal
That's really nice! What's the equation you used?

@TIG
Make sure you have the latest version of Recurve. I fixed that bug with the last update which is why I couldn't reproduce the error. If you ever get the SurfaceGen error again let me know.

@Pilou
Just re-select the group with the select tool. It seems that the SelectionObserver doesn't fire when the selection is changed in code.

[TIG]

You are right, in that when I get v1.4 of 'recurve' I no longer get these errors with 'surfacegen'. However, I had v1.3 [with SUpv8] and there were no major changes except for making it SUpv6 friendly ?
Anyway... no more error messages... I'll try to break it

[Builder Boy]

Sponge-like object:

Capture1.PNG

[driven]

this is great,

some odd behavior on the Mac... when run from plugins (like you should) I get this

Code: Select all

Error: #<ArgumentError: Cannot convert argument to Sketchup::Point3d>
/Library/Application Support/Google SketchUp 8/SketchUp/Plugins/SURFACEGEN_Dir/surfacegen_tool.rb:266:in `add'
/Library/Application Support/Google SketchUp 8/SketchUp/Plugins/SURFACEGEN_Dir/surfacegen_tool.rb:266:in `getExtents'

if I put the surfacegen.rb into the folder do a restart and then load from Ruby Code Editor, I get this

Code: Select all

(eval):428: warning: don't put space before argument parentheses
"Run aborted (error has occurred)"
(eval):428: warning: don't put space before argument parentheses
(eval):10: warning: already initialized constant SURFACEGEN_DIR
(eval):11: warning: already initialized constant GRAPH_SIZE
(eval):12: warning: already initialized constant WINDOW_HEIGHT
(eval):13: warning: already initialized constant ATTR_DICTIONARY
"Run aborted (error has occurred)"

but if I restart again and use as_pluginloader.rb to load it I get

Code: Select all

/Library/Application Support/Google SketchUp 8/SketchUp/plugins/SURFACEGEN_Dir/surfacegen.rb:428: warning: don't put space before argument parentheses

it works, but has no tool button image...

surfacegen_mac.png

button image-no dialog.png

[notareal]

@notareal
That's really nice! What's the equation you used?

Code: Select all

F(x,y,z) = 2-(cos(x+(1+sqrt(5))/2*y)+cos(x-(1+sqrt(5))/2*y)+cos(y+(1+sqrt(5))/2*z)+cos(y-(1+sqrt(5))/2*z)+cos(z-(1+sqrt(5))/2*x)+cos(z+(1+sqrt(5))/2*x))*16/(x*x+y*y+z*z)
[x]: -5, 5
[y]: -5, 5
[z]: -5, 5

There is plenty more at the k3dsurf forum.

[notareal]

Perhaps you could add some more functionality; like functions min, max and abs. Also allow use of arithmetic operations and pi in axes, like -2*pi.

[TIG]

You already have 'pi' [in lowercase] as a function?

Capture.PNG

[thomthom]

@Pilou
Just re-select the group with the select tool. It seems that the SelectionObserver doesn't fire when the selection is changed in code.

The SelectionObserver has always been very buggy: http://www.thomthom.net/software/sketchup/observers/

[Diggsey]

Just uploaded a fairly major update to the first post!

@driven
This should fix the issues with macs. It now uses cross-platform methods to locate and load resource, and uses show_modal rather than show on macs with the WebDialog.

@notareal
The axes now let you use an expression such as 2*pi

@d12dozr
Helpful error message are now shown when an expression is invalid.

[TIG]

Thanks

Code: Select all

Error: #<ArgumentError: Cannot convert argument to Sketchup::Point3d>
C:/Program Files/Google/Google SketchUp 8/Plugins/SURFACEGEN_Dir/surfacegen_tool.rb:270:in `add'
C:/Program Files/Google/Google SketchUp 8/Plugins/SURFACEGEN_Dir/surfacegen_tool.rb:270:in `getExtents'

One minor error in getExtents in surfacegen_tool.rb
Line #270 result.add @p0 if @state >= 0
can raise an error so adjusting it to
return if !@p0 or @p0.class!=Geom::Point3d; result.add @p0 if @state >= 0 might help - you could also add similar validity checks on the other points that are added to the extents ?

[Diggsey]

Ah, I knew I'd forgotten something

I've updated the first post. It shouldn't show those errors anymore.