NURBS plugin version 0.1

Dan Rathbun

Other issues:

I use the word "knurbs" because it's by Mr.K (yes.. reminds me of Linux KDE apps.)

Files should be in a "author/knurbs" subfolder below the Plugins folder, not in the Plugins folder itself.
Needs a "knurbs_ext.rb" registration script in the Plugins folder, to allow users to activate / deactivate it from the Preferences > Extensions dialog.
The require() statement for the DLL dependancy needs to go at the top of the rb file, within a begin ... rescue .. end block, so that the rest of the ruby code only loads if the DLL/DYLIB file is found. Block needs a rescue LoadError clause to inform user that the DLL cannot be found.
The plugin code needs to be wrapped in an Author::KNURBS namespace!!

Currently the methods are being defined within Object, and are propagating into ALL Ruby objects. This is a NO-NO.* The global vars need to be converted to either local, instance, or class vars, within the plugin's namespace. (Globals should only be used if they are to be shared with ALL plugins.)

The plugin is currently Windows only as it uses a DLL, and the Win32API class to call the C++ side functions.

Needs the C++ side functions wrapped to expose them to Ruby (within the plugin's Ruby-side namespace.) Win32API will no longer be needed, as require() can load DLL and DYLIB files.
Needs an edition compiled with Xcode on Mac, as a DYLIB file.

Dan Rathbun

The UI will need to be a Tool class (or several of them.)

Within a Tool the draw() method can draw temporary geometry (that is not added to the model.)

Note the Sketchup OpenGL constants that can be used with View.draw()

GL_LINES GL_LINE_LOOP GL_LINE_STRIP GL_POINTS GL_POLYGON GL_QUADS GL_QUAD_STRIP GL_TRIANGLES GL_TRIANGLE_FAN GL_TRIANGLE_STRIP

Also, take note of the other View class draw methods. These must be used within a Tools instance.

See Fredo6's BezierSpline Plugin plugin for examples.

Rich O Brien

Error Loading File NurbsPlugin.rb
127; The specified procedure could not be found.   - Init_Nurbs
C;/PROGRA~2/Google/GOOGLE~1/Plugins/Nurbs.dll

Nurbs.dll is in my plugins folder. Is this v7 only?

Mr.K.1

@unknownuser said:

Error Loading File NurbsPlugin.rb
> 127; The specified procedure could not be found.   - Init_Nurbs
> C;/PROGRA~2/Google/GOOGLE~1/Plugins/Nurbs.dll

Nurbs.dll is in my plugins folder. Is this v7 only?

That is only Ruby trying to call an initialization command in DLL which doesn't exist, I tried adding some empty ones to get around the error message but nothing fixed it sofar.

This is only the first crack at the plugin, and I see I got alot of corners to trim.

solo

Whooho!!

Cannot help you with code, but mate I'm here with encouragement.

Rich O Brien

I played with the car model and so far it's pretty good. Have you seen n-gon's Bezier Patch plugin?

Mr.K.1

Nope did not spot that, and I started work on this because I couldn't find any Sketchup surface builders anywhere.
Thanks for the heads up, guess I'm off the hook then

I'm just gonna wrap this one up into a slightly more wholesome package and direct people to the other version.

Dan Rathbun

@unknownuser said:

@unknownuser said:

Error Loading File NurbsPlugin.rb
> > 127; The specified procedure could not be found.   - Init_Nurbs
> > C;/PROGRA~2/Google/GOOGLE~1/Plugins/Nurbs.dll

Nurbs.dll is in my plugins folder. Is this v7 only?

That is only Ruby trying to call an initialization command in DLL which doesn't exist, I tried adding some empty ones to get around the error message but nothing fixed it sofar.

This is only the first crack at the plugin, and I see I got alot of corners to trim.

Actually the DLL is NOT a Ruby C extension, so cannot be loaded with require() (at this time.)
As it's accessed via the Win32API class... for now just comment out the line
require 'Nurbs.dll'
as it doesn't do anything anyway.

Dan Rathbun

Looking thru the CPP file, I dont see anything that couldn't just be written in pure Ruby. (might be slower of course.)

Mr.K.1

But if I remove require() Win32API doesn't find the file at all... and I'm guessing using a full path would actually fix that.

Yes the C++ code is fairly simple, I thought interfacing a working example with Ruby would be simple to make and compute faster, but as it turns out it needs alot of array transformations(which were nibbling away at my sanity) plus the added time cost of those it is very questionable if a direct Ruby compute would be any slower.
And since drawing is the real time hog it doesn't really matter.

How is thomthom doing the Bezier Surface? Ruby only?

Dan Rathbun

@unknownuser said:

But if I remove require() Win32API doesn't find the file at all... and I'm guessing using a full path would actually fix that.

Yes... normally the DLLs used are system files like user32.dll etc. so the OS knows where to find them.

The default working dir when Ruby starts is the HOME dir... ENV['USERPROFILE'] but you can save it, change it, use it and restore it.

Your also creating a new Win32API instance each time that method is called.
It would be simplier to create a reference to the call outside the method:
olddir = Dir.getwd Dir.chdir(File.expand_path(File.dirname(__FILE__))) @nurbs = Win32API.new('Nurbs','nurbs', ["p","p","p"],"L") Dir.chdir(olddir)

then within the method
@nurbs.call(@a,@b,@c)

Dan Rathbun

@unknownuser said:

How is thomthom doing the Bezier Surface? Ruby only?

dunno.. he's on vacation.

Dan Rathbun

@dan rathbun said:

See Fredo6's BezierSpline Plugin plugin for examples.

SO.. was Fredo's utility what you wanted, but could not find it because he didn't use the word "NURBS" ??

Mr.K.1

I was looking for a surface builder, don't know if I'm missing something but Fredo's BezierSpline just does 2D curves.

But if there already is any sort of SU surface builder in existance I would love to know about it.

Dan Rathbun

@unknownuser said:

I was looking for a surface builder, don't know if I'm missing something but Fredo's BezierSpline just does 2D curves.

But if there already is any sort of SU surface builder in existance I would love to know about it.

Fredo's (Beta) CurviLoft

Now once a surface mesh is created, the built in tools lack power. If ThomThom is working on a mesh editor tool, then you just KNOW it will be a good one!

Add:

SoapSkin Bubble

SurfaceGen

Mr.K.1

YES! Curviloft is exactly what I wanted, thank you.

Now I can move on to other projects, and it makes this thread/topic obsolete, could someone please remove it?

Rich O Brien

Are you sure about removing this?

Dan Rathbun

I don't mind... the code was way before alpha!

Just a rudimentary example of concept.

Users would be better off using one of the mesh / surface packages from the Plugins forum.

Mr.K.1

Exactly, I don't want other users stumbling upon my poor attempts at reinventing water when there are so many well done plugins available.

If I ever get back to finishing this I'll post a new thread, but right now this thread is of no value and should be deleted.

fredo6

Dear Mr.K

If you have a C/C++ library containing Surface Nurbs functionality, I am interested to have a look and possibly build the SU GUI around it.

As you noticed, Curviloft (or ExtrudeEdgeByxxx by TIG) are not really Nurbs modelers, but use splines and bezier curves to generate surfaces based on coons, stretching and averaging. Real surfacic Nurbs are more powerful, but for performance reasons the calculations must be done in C. The closest I know to be a real surfacic modeler is

BezierPatch by Victor Liu
BezierSurface by ThomThom
TGI3d (probably based on true Nurbs)
Artisan by Whaat
Soap, Skin & Bubble
FerrariSketch
maybe others that I am not aware of

If your package includes Nurbs curves only, then it is more something that is today in BezierSpline and that I will definitely include in a more advanced form in the refresh of this plugin.

Thanks

Fredo