DrawPoints - Invalid object length

Helper

On 17/08/2015 at 01:23, xxxxxxxx wrote:

I am using ScottA PyDraw Smooth Spline plugin to put a spline on the view (HUD), but I am getting a
"ValueError: Invalid object length".
Searching the forum, there are some issues, but no solution yet?

I am using R15 and R16.

        cntrl_points = [cntrl_p1,cntrl_p2,cntrl_p3,cntrl_p4] #A list array containing the control points
        bd.SetPointSize(5.0)                                 #Set the size of the points		
        col = [.9, .1, .1]*4                                 #Set the color of the CV points	
        bd.DrawPoints(cntrl_points, col, 3, None)	         #Draw the spline Control Points

Helper

On 17/08/2015 at 04:39, xxxxxxxx wrote:

Hi Pim,

Yes there seem to have in issue in BaseDraw.DrawPoints() with its last argument 'vn' for the points normal when it's None. To have it work pass a valid list of normals (same number as point counts). This issue will be fixed.

In the code of the PyDraw Smooth Spline:
- Pass norm = [c4d.Vector(1)]*4 for the first call to DrawPoints() (4 points)
- Pass norm = [c4d.Vector(1)]*13 for the second call to DrawPoints() (13 points)
- The line cadr = [1]*924 for the second call to DrawPoints() is wrong, it has to be miltiplied by 39 only (13*3).

If you find any bug or issue do not hesitate to submit it because the forum isn't a repository for bugs and they can be lost in threads (this one was).

Helper

On 17/08/2015 at 06:56, xxxxxxxx wrote:

Thanks Yannick , it is working now.

Another question: Is there a faster/ better way to select one of the point or handles of the spline in the HUD?
ScottA uses the mouse position and compares it with the position of the points.

-Pim

PS Before I submit a bug, I like to be sure that it is not an error from my side.

Helper

On 17/08/2015 at 07:48, xxxxxxxx wrote:

I just found that to make it work simply omit passing 'vn' parameter i.e. call DrawPoints() with only 3 parameters.

Originally posted by xxxxxxxx

Another question: Is there a faster/ better way to select one of the point or handles of the spline in the HUD?
ScottA uses the mouse position and compares it with the position of the points.

I think the mouse checks to get the current control point moved should be done in MouseInput() after the call to win.MouseDragStart(), not in GetCursorInfo().

Originally posted by xxxxxxxx

PS Before I submit a bug, I like to be sure that it is not an error from my side.

The issue can be reproduced if None is passed for 'vn' parameter and I think there's the same issue with 'vc'.

Helper

On 17/08/2015 at 07:59, xxxxxxxx wrote:

All clear now, thanks again.

Helper

On 24/08/2015 at 02:31, xxxxxxxx wrote:

I works ok in R15, but in R16, the spline is displayed twice. Once in the view port / Hud and once normal.

Here the code Draw:

    def Draw(self, doc, data, bd, bh, bt, flags) :	
	
        ################# This is the control points section ####################
  
        p1x = myDict['cp1x']
        p1y = myDict['cp1y']		
        cntrl_p1 = c4d.Vector(p1x,p1y,0)     #The first control point(the start of the spline)
		
        p2x = myDict['cp2x']
        p2y = myDict['cp2y']
        cntrl_p2 = c4d.Vector(p2x,p2y,0)     #The second control point
		
        p3x = myDict['cp3x']
        p3y = myDict['cp3y']		
        cntrl_p3 = c4d.Vector(p3x,p3y,0)      #The third control point
		
        p4x = myDict['cp4x']
        p4y = myDict['cp4y']			
        cntrl_p4 = c4d.Vector(p4x,p4y,0)     #The fourth control point(the end of the splne)
		
        cntrl_points = [cntrl_p1,cntrl_p2,cntrl_p3,cntrl_p4] #A list array containing the control points
        bd.SetPointSize(15.0)                                 #Set the size of the points		
        col = [.9, .1, .1]*4                                 #Set the color of the CV points	
        bd.DrawPoints(cntrl_points, col, 3)	         #Draw the spline Control Points		
  
        ################# This is the spline's points section ####################
        steps = myDict['segments']                        #The number of line segments 
        s_points = smoothPoints(cntrl_points, steps)      #The points of the spline		
        cadr = [1]*924                                    #Set the color values for the points				
        bd.SetPointSize(3.0) 
  
        bd.DrawPoints(s_points, cadr, 3)	          #Draw points so we can see where each line in the spline begins/ends
  
        print "_points: ", s_points
        #Create a line between two points (except the last point) to create a spline
        size = len(s_points)		
        for i in xrange(0,size-1) :
            bd.SetPen(c4d.Vector(1, 1, 1))                #Set color for draw operations
            bd.DrawLine2D(c4d.Vector(s_points[i].x,s_points[i].y, 0) , c4d.Vector(s_points[i+1].x,s_points[i+1].y, 0))		
		
        c4d.EventAdd()        
        return c4d.TOOLDRAW_HANDLES|c4d.TOOLDRAW_AXIS

In the documentation I do not see any relevant changes in R15 to R16.

Also, is there a way to display and use Tangents in the viewport / Hud?

Helper

On 24/08/2015 at 05:49, xxxxxxxx wrote:

Changing bd.DrawPoints to bd.DrawPoint2D seems to solve the issue.
Now only the 2d is shown.
Of course, bd.SetPointSize is not used. Only a one pixel point is displayed using DrawPoint2D.

Still trying to find out how to display / set tangents.

-Pim

Helper

On 24/08/2015 at 07:33, xxxxxxxx wrote:

Hi Pim,

I wrote this plugin using R13. And it works properly with that version.
But Maxon keeps on making major changes to the SDK. Especially the Python SDK.
So try not to follow my code too closely. Just use it as a general guide.

With all of the change they make to the SDK from version to version.
You might have to completely re-write it for R16++.

-ScottA

Helper

On 24/08/2015 at 08:01, xxxxxxxx wrote:

Hi Scott,

Thanks again for all your plugins and yes I use them mostly as guidelines.
I learn a lot that way.
It is step by step, but I think I am getting there.
Now the main issue is, how to get the tangents.

-Pim

Helper

On 25/08/2015 at 01:12, xxxxxxxx wrote:

Hi Pim,

You can also use bd.DrawLine2D() to draw tangents.

Helper

On 25/08/2015 at 04:44, xxxxxxxx wrote:

Ok, does that means I must write my own tangent calculation or can I use sdk functions / routines?

Helper

On 25/08/2015 at 06:13, xxxxxxxx wrote:

Originally posted by xxxxxxxx

Ok, does that means I must write my own tangent calculation or can I use sdk functions / routines?

You may use the spline data and calculation in the API provided by SplineData.

Helper

On 25/08/2015 at 07:43, xxxxxxxx wrote:

The only reason why my plugin exists at all is because the C4D SDK doesn't have any 2D Spline Draw classes in it.
And when I asked for help with how to make them myself. All I got were crickets chirping.

After weeks and weeks of searching the internet for examples. I found mostly just the maths posted for this subject.
The math for splines is quite complex. And not easy to convert into computer code.
It took me quite a lot of time and effort to figure out how to draw a 2D spline to the Editor view in C4D. Too long!
I did not want anyone else to have to go through the same hell I went through just to draw a smooth cubic spline in 2D. So I posted my code for everyone to see how simple it is, once you have the complex maths converted into computer code.

So if there are people out there that do know how to write the tangents code part for this. Or even have other types of code for drawing splines in their tool kit. Please do what I did, and pay it forward and post an example for the rest of use to learn from.
Posting a bunch of complex maths to WIKI does not help. We need to see it in code form.
This is one of those subjects where finding good simple code examples was very difficult to find.

Thanks,
-ScottA

Helper

On 25/08/2015 at 12:23, xxxxxxxx wrote:

I have the following options /thoughts, I still need to investigate.

1) C4dJack wrote an article on c4dprogramming on "drawing a spline in the viewport".
I want to use that as a start, assuming viewport = hud. So a 2d spline.

2) To calculate tangent, I want to use the code Martin provided:

    
    
        #_______________________________________________________  
      #Soft interpolation  
      lenRight = (pointList[i+1] - pointList[i]).GetLength()  
      lenLeft = (pointList[i-1] - pointList[i]).GetLength()  
      lenAverage = (lenLeft + lenRight)/2  
      if lenAverage > lenRight:  
          lenAverage = lenRight  
      elif lenAverage > lenLeft:  
          lenAverage = lenLeft  
      orientation = (pointList[i+1] - pointList[i-1]).GetNormalized()  
      tangent = orientation * lenAverage / 4  
      spline.SetTangent(i, -tangent, tangent)

3) And of course SplineData as Yannick said.
"You may use the spline data and calculation in the API provided by SplineData."
I will asked him to elaborate on this (give me more details).

These are just some thoughts I still need to investigate.

-Pim

Helper

On 25/08/2015 at 12:25, xxxxxxxx wrote:

Originally posted by xxxxxxxx

Originally posted by xxxxxxxx

Ok, does that means I must write my own tangent calculation or can I use sdk functions / routines?

You may use the spline data and calculation in the API provided by SplineData.

Hi Yannick,

Could you elaborate a bit more on what you mean.
If possible, more details, directions to display a 2d (hud) spline.

-Pim