equations

[kamate]

Is it possible to write a script for visualizing equations like
cos x * sin y + cos y * sin z + cos z * sin x = 0 or
(1-cos x)*cos x +(y+sin x * sin z +cos (x+z) =0 ?
which chapters of the scripting guide do i have to study for this? (importing the data from other programs loses to much quality)

thanks in advance

[att-2]

I guess you want to get values from those equations. OK. Using JavaScript is quite simple. You have an object named "Math" and a couple of methods "cos" and "sin". So, you have the elements.

Your first equation could be:
Math.cos (x) * Math.sin (y) + ... etc ...

[kamate]

Actually i want to generate a surface model.If this works with values an example would be really fine. Because you mention the need of an object i think you may speak of the expression editor?
Do you think any non-specific javascript to generate 3d surfaces will work in the script editor?

I guess you want to get values from those equations. OK. Using JavaScript is quite simple. You have an object named "Math" and a couple of methods "cos" and "sin". So, you have the elements.

Your first equation could be:
Math.cos (x) * Math.sin (y) + ... etc ...

i guess you first have to solve for x(u,v) y(u,v) z(u,v) and define the parameter range.

[shanesternstein]

This is a quick response because I have to get to bed.

If you use NURBS surfaces you're working with finite samplings of a smooth function.

Based on stepping values you move along an axis (say X) and at that plane you minimise the function so it has only 2 parameters.
Then you move along another axis (say Z) and you solve for Y and based on that point you draw a Interpolated Nurbs Curve along this X-defined plane. The reason you use Interpolated Nurbs curve is because the points you draw actually go through the the curve, and aren't used to weight the curve.
You make a new curve for each step along your X-axis until you reach your end boundary value. At that point you simply select all the curves and skin them together.

It's pretty simple I must say.

Tomorrow I'll post the code for it.

Remember though, the surface won't be an exact representation, because you're working with NURBS, which are essentially polynomial defined curves. I wouldn't recommend XSI for accurate displaying of mathematical surfaces at all, because it is primarily an artistic tool - not a mathematics package like MatLab or Mathematica (which I use for Math work).

Vijay @ Dream Interactive....

[att-2]

No, I was talking about a script, but it also works in the expression editor.

You can use JavaScript or VBScript in the script editor.

If you want to make a 3d surface I guess you would like to work with NURBS. I haven't tried the following but I think I'd have to work. The first think you have to do is build a grid with NURBS:

• CreatePrim ("Grid", "NurbsSurface", null, null);
  Then you have to select the control vertex of the grid in order to modify it as following:
• SelectGeometryComponents ("grid.pnt[(7,6)]")
  Finally you have to modify the control vertex position:
• Translate (null, -0.023, 0.522, 0.000, siRelative, siView, siObj, siXYZ, null);

You could use the Math.cos () or Math.sin () to modify the control vertex position. For instance:
- Translate (null, 0, Math.cos (45), 0, siRelative, siView, siObj, siXYZ, null);
You have to iterate all the grid control vertex and modify them as you want.

I think it would be better and easier to use a grid NURBS to build your surface than build the surface from the scratch. Obviously the surface is an aproximation to the surface you would like to get.

[kamate]

county

i have got some good imported models from math programs. unfortunately the models have 3sided polys, so the geometry approximation nearly does not show any effect. but they are good enough to take over the hill and valley construction points. simple? - i never tried it out, but it looks like a lot of work. maybe your code makes it easier.

att 2

thanks for your idea. to deform a grid into a surface like that above will exeed my capacity i guess. a friend wants to send me a javascript therefore from another program - hope that works.

newton

[shanesternstein]

"i have got some good imported models from math programs. unfortunately the models have 3sided polys, so the geometry approximation nearly does not show any effect. but they are good enough to take over the hill and valley construction points. simple? - i never tried it out, but it looks like a lot of work. maybe your code makes it easier."

Sorry I didn't write the code like I said. I've been viciously busy.

Anyway, My code would use NURBS, not polygons. And using my algorithm you can't have discontinuity along any base axis. Making code using NURBS to allow for that would be a bitch! - to say the least. The structure you displayed is a very complex structure, and NURBS are inadequate to represent the mathematical model.

Your best bet is to use polygons, but not in XSI. And the approach you take would depend specifically on the type of and structure you're creating. Importing from another mathematical package might work.

Sorry I couldn't have given more assistance,

Vijay @ Dream Interactive....