Vicente wrote at 2010-08-03 20:00:

I'm working currently on a 3D project and I'm using Helix for the cameras and the viewport (great work :)). I have noticed a strange behavior that I don't understand much regarding the camera, the movement of the camera and the ZoomToFit method.

For the first part of the project I was working with GeometryModel3D objects, creating the geometry by hand (positions, triangle indices,...) and assigning them their transforms. Everything worked right. Now I have refactored the code base and I have started using ModelVisual3D and I assign the transform there instead of transforming the GeometryModel3D. Now the ZoomToFit doesn't catch the object, the camera moves strangely and when that transform is big enough, everything starts doing pretty weird things.

I have looked at Helix samples and the behavior is similar to the one in the Simple Demo, in the Transformed Model tab. So I suppose that is by design, but I don't really understand the difference or what's happening behind the scenes :)

Could you give me an explanation of why are both things giving so different results? Regards!

Vicente

objo wrote at 2010-08-04 09:02:

hi Vicente! It is good to hear you find the toolkit useful! I just added support for transforms in the ZoomToFit method, and an example in the SimpleDemo. Make sure that your viewport control is loaded before calling the ZoomToFit method. It seems to behave correct now :) Also note that you can use mouse double right click to set the camera LookAt point.

objo wrote at 2010-08-05 00:54:

I corrected a bug in the transform calculation. It should work now, also for combinations of transformations :)

Vicente wrote at 2010-08-06 18:52:

Hi objo!

thanks a lot for the changes :) I have been playing more with the transformations and I have hit another weird thing. It seems the camera translation (middle mouse button) depends on the translation of the object, rotation and zoom. For example, if you have a translation in the object of (200, 150, 100), sometimes moving the mouse to the left will move the object to the left, but depending on the zoom, in some other cases it will move the object to the right, as if the axis got inverted. It's easy to see in the Zoom to Fit tab in the Simple Demo. Also, if the translations are bigger, the camera starts behaving very strangely, and double clicking with the middle mouse button doesn't seem to work correctly.

It looks like a bug to me, but not sure, if you need more information on how to reproduce it let me know. Regards!

Vicente

Vicente wrote at 2010-08-07 03:18:

By the way, I have found also another strange camera behavior. If you try using ZoomToFit with an empty scene, the camera will get "not a number" values in the Position property, and from there it will go crazy, it will never work again. If you try ZoomToFit again after that, it will crash in CameraHelper.cs line 115. If you have an scene with something, then empty it and you try ZoomToFit you get the exception in the same place but related to the newPosition value.

Hope it helps :) Regards!

Vicente

objo wrote at 2010-08-12 09:56:

Vicente wrote at 2010-08-13 14:30:

ReedCopsey wrote at 2010-10-21 03:19:

objo,

Any progress on the strange camera behavior with panning?  This has been causing us grief lately.

Thanks,

Reed

objo wrote at 2010-10-21 06:58:

hi Reed,

no, I have not had any progress on that problem. It could be a problem in the Ray3D.PlaneIntersection algorithm... I'll add this to the issue tracker.

I just corrected a similar problem with the zoom - when scrolling very fast you might end up on the 'other side' of the object. The solution there was to clamp the zoom factor.

cheers objo 

Rogad wrote at 2014-02-20 15:52:

objo wrote at 2014-02-20 20:36:

Rogad wrote at 2014-02-20 21:19:

objo wrote at 2014-02-20 22:40:

Rogad wrote at 2014-02-20 23:35:

Rogad wrote at 2014-02-20 23:36:

Rogad wrote at 2014-02-21 15:52:

Rogad wrote at 2014-02-21 18:16:

Rogad wrote at 2014-02-27 19:33:

Rogad wrote at 2014-02-28 17:53:

mcrxb wrote at 2012-02-24 20:51:

Hi,

I'm using LinesVisual3D to produce an outline which works great. The problem I'm running into is having multiple outlines on screen with different properties (thickness, color, etc.). Both LineVisual3Ds are using the points from each other and creating overlapping lines. Here's a code sample:

TaperMillMainViewport.Children.Clear();

LinesVisual3D centerline = new LinesVisual3D();
centerline.Color = Colors.Gray;
centerline.Thickness = 1;
centerline.Points.Add(new Point3D(0, 0, 0));
centerline.Points.Add(new Point3D(0, 2, 0));
TaperMillMainViewport.Children.Add(centerline);
            
LinesVisual3D profile = new LinesVisual3D();
profile.Color = Colors.DarkGreen;
profile.Thickness = 2;
profile.Points.Add(new Point3D(0, 0, 0));
profile.Points.Add(new Point3D(.25, 0, 0));
profile.Points.Add(new Point3D(.25, 2, 0));
profile.Points.Add(new Point3D(0, 2, 0));
TaperMillMainViewport.Children.Add(profile);

objo wrote at 2012-03-10 15:36:

thanks for the bug report! There was a bug in the initialization of the Points dependency property - it should be corrected now. 

Also note that the Points list should contain pairs of coordinates - for each line segment. Your "profile" element will only contain two line segments.

ManyMiles wrote at 2012-05-21 18:26:

I am very new at the Helix 3D Toolkit, and I'm excited to learn more about it.

I would like to have multiple sets of gridlines. Currently I'm just trying to get 2 sets to show, but it seems like it will only register one.  I'm trying with 1 grid in the X-Y Plane and 1 in the X-Z plane.  Is it possible to include multiple GridLinesVisual3D elements in the view?  What is an easy way to do it?  

Currently I have this declared in the MainWindow method ...

var model = new ModelVisual3D();
model.Children.Add(new GridLinesVisual3D() { Center = new Point3D(-0.5, -0.5, -0.5), Normal = new Vector3D(1, 0, 1), Width = 20, Length = 20, MinorDistance = 1, MajorDistance = 10, Thickness = 0.04, Fill = Brushes.Green });
model.Children.Add(new GridLinesVisual3D() { Center = new Point3D(-0.5, -0.5, -0.5), Width = 20, Length = 20, MinorDistance = 1, MajorDistance = 10, Thickness = 0.04, Fill = Brushes.Red });
view1.Children.Add(model);

But it seems to only show the second Grid.  Thanks for your help.

objo wrote at 2012-05-26 08:55:

Try to set LengthDirection = new Vector3D(0,1,0) on your first set of grid lines.

The 'WidthDirection' is calculated as the cross product of Normal and LengthDirection. In your code you end up with the same length and width directions in both cases.

See the GridLinesVisual3D.Tessellate method how it works.

ManyMiles wrote at 2012-05-29 01:39:

Thanks very much.  Setting the Normal and LengthDirection attributes got exactly the desired result I needed.

alessio83 wrote at 2013-09-12 11:10:

a5r wrote at 2013-09-16 11:31:

alessio83 wrote at 2013-09-16 16:07:

a5r wrote at 2013-09-16 16:41:

alessio83 wrote at 2013-09-16 17:05:

objo wrote at 2013-09-17 00:17:

afra89 wrote at 2011-12-23 12:17:

I have several CubeVisual3D objects. Can I somehow make them a single group and then I rotate that group so all of the cubes rotate. Is this possible?

objo wrote at 2011-12-23 12:22:

See

http://msdn.microsoft.com/en-us/library/system.windows.media.media3d.modelvisual3d.children.aspx

afra89 wrote at 2011-12-23 12:41:

Thanks for quick answer, it works.
The problem is that I want to rotate them in the center of the whole modelgroup. 

This is my code:

RotateTransform3D rt;         
AxisAngleRotation3D ar;           
Transform3DGroup grp;

rt = new RotateTransform3D();           
ar = new AxisAngleRotation3D();                       
ar.Axis = new Vector3D(1, 0, 0);           
ar.Angle = x;           

rt.Rotation = ar;           
rt.CenterX = *Here i need center of the group X*       
rt.CenterY = *Here i need center of the group Y*           
rt.CenterZ = *Here i need center of the group Z*

grp = new Transform3DGroup();           
grp.Children.Add(rt); 
                     
cubes.Transform = grp; 

objo wrote at 2011-12-23 12:50:

here is a great book on 3D programming with WPF:

http://www.amazon.com/Programming-Windows-Three-Dimensional-Presentation-Foundation/dp/0735623945

the mathematics behind transformations is well covered here!

Jano42 wrote at 2013-03-27 14:10:

 <helix:HelixViewport3D x:Name="_helixView" Loaded="HelixViewLoaded" >
            <helix:DefaultLights/>
            <ModelVisual3D x:Name="_helixModel3D" Content="{Binding CurrentModel}"/>
...

Elementu wrote at 2012-01-17 10:24:

Hello ,

I am using the Helix 3d toolkit to develop my solution.

What I need and have not yet managed to develop properly is the drawing of a cube, or for that matter any other figure, with the mouse.

So when I press the left click I need the cube to begin drawing , as I keep dragging the mouse the cube should increase in size until I release the mouse button. at which moment the drawing should stop and the cube should be completed.

Unfortunately when drawing the cube i use the "HelixToolkit.Wpf.CubeVisual3D" which only has the center property and the size(width, height, depth) properties. so I am having problems drawing like any 3d program would , that is when when starting the drawing one corner should be fixed and the other points should mode until the drawing is complete. I thought of making the cube out of lines but that only applies to the cube and I also need to draw cylinders polygons   and others.

One more problem I am facing is that I assigned the rotation of the camera to the left click instead of the right click as it is usually. So that works for me only that when I select a figure to draw the left click should be used to draw and not to rotate the camera anymore until the selected button with the figure to draw is deselected then the left click is assigned back tot the rotation function.

Can anyone please point me in a right direction in order to solve this problems?

Thanks in advance.

objo wrote at 2012-01-17 11:33:

CubeVisual3D: right, you have to change the center point when you want to keep one corner (P1) fixed:

Center = P1 + new Vector3D(1,1,1) * SideLength * 0.5;

Rotate/draw modes: Can you set the RotateGesture to a MouseGesture(MouseAction.None) while you are in the draw mode?

I will add a box-drawing example when I get time :)

elementu wrote at 2012-01-17 12:36:

Thank you for your quick reply, i have tried to move the center instead of keeping it fixed but whatever I tried failed because the cube was still growing in both directions so i did not get the fixed corner I was hopping . I will try this too.

Another thing is that I get the mouse position like this HelixViewport.CurrentPosition to get a Point3D object in order to check how much the position of the mouse has changed . But if I cross an object that I already have loaded in the viewport the coordinates I get from the "CurrentPosition" property are very different and I barely move the mouse this is most visible when I have the grid lines loaded and i pas over the lines. What could be the nature of this problem ?

I will try to set the gesture to MouseAction.None when in draw mode. Actually I have thought of doing this before but wanted to modify as little as I could in the Helix code so that I don't have conflicts in other parts of the toolkit. So i tried to catch the mouse down event outside but the handler I was using was not getting triggered. the mouse up and move events were triggered i user it like this :

<h:HelixViewport3D
                           MouseLeftButtonDown="viewport_MouseLeftButtonDown"
                           MouseLeftButtonUp="viewport_MouseLeftButtonUp"
                           MouseMove="viewport_MouseMove"/>