(03-29-2020, 12:29 PM)close Wrote: Hi kreativasas,

when you applying transformations you have to add the new one to the existing transformations.

This code takes the existig transformations of the Visual3D and add a new one each time. 

Code:

       public static void AddRotationTransformation(Visual3D pVisual3D, Vector3D pVector3DAxis, double pAngle)
       {
           // get the transformation from the axis and angle
           RotateTransform3D rotateTransform3D = new RotateTransform3D(new AxisAngleRotation3D(pVector3DAxis, pAngle));

           // if there is no transformation yet apply the rotation transformation directly and return
           if (pVisual3D.Transform == null)
           {
               pVisual3D.Transform = rotateTransform3D;
               return;
           }

           Transform3DGroup transform3DGroup = (Transform3DGroup)pVisual3D.Transform;
           // check the transform3DGroup of the visual already exists
           //      -> if not create a new one and add it as transform to the visual
           if (transform3DGroup == null)
           {
               transform3DGroup = new Transform3DGroup();
               transform3DGroup.Children.Add(pVisual3D.Transform);
               pVisual3D.Transform = transform3DGroup;
           }

           // add the transformation to the transformGroup
           if (transform3DGroup.Children.Count > 0)
               transform3DGroup.Children.Insert(0, rotateTransform3D);
           else
               transform3DGroup.Children.Add(rotateTransform3D);
       }

You can call the method like this:

Code:

       private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
       {
           TransformTest.AddRotationTransformation(RootModelVisual3D,new Vector3D(1,0,0), 10);
           TransformTest.AddRotationTransformation(RootModelVisual3D_2,new Vector3D(0,1,0), 42);
       }

Maybe this link helps: 
https://docs.microsoft.com/en-us/dotnet/framework/wpf/graphics-multimedia/3-d-transformations-overview

The Ab3d sample is here:
https://github.com/ab4d/Ab3d.PowerToys.Wpf.Samples/blob/master/Ab3d.PowerToys.Samples/Utilities/ModelRotatorSample.xaml.cs

(03-30-2020, 12:15 PM)close Wrote: The upper method takes the current transormation and applies the new one to the obj.transformation w/o any global variables. If you apply an global variable as transformation the reference will be stored inside the obj.transformation and this results in an behavior like you describe. Are you using VB?