Trail


By moving the Trail object in virtual space, for example by attaching it to a traveling spaceship or any other moving object in your project, you can render a 3d trail.

You can use this object for ammunition tracers, tire-marks, continuous smoke trails, reference lines and so on.

Trail shape, colors, opacity, lifetime and smoothness are definable and some presets are included.

The trail emitter is an object you can place and orient visually in the Virtual Editor.



Change

Click this button to select the trail segment aspect. You can make your own trail shapes as follows:

  • By using your favorite paint program, make a picture which includes an alpha (opacity) layer. The alpha map is used to make parts of your picture transparent. See the documentation for your paint program for details about alpha layers.


  • To guarantee compatibility with all systems, the image should be power-of-two-sized, like for example 256x256, 128x512 and so on.


  • Save your picture to .tga, .png or .dds format to the

    C:\3D Rad\3DRad_res\objects\Trail\Data\

    folder.


  • Resize your picture to 128x128 pixels and save it again as a .jpg file to the

    C:\3D Rad\3DRad_res\objects\Trail\Data\Index\

    folder. This image will be used to display your new shape in the Trail object's dialogs and make it selectable among the other shapes available.


    • Parent bone ID

    When this value is non-zero, and the Trail object is linked to a SkinMesh which is bone-animated, the trail emitter will be attached to the SkinMesh's bone defined by the specified bone ID.

    The bone ID must be a positive, non-zero integer. The first bone in the model is 1, the second 2 and so on. What bone corresponds to a certain ID depends on how the animated model was originally designed.

    Note: the position of the attached trail emitter is relative to the bone position when the animated model is in its initial pose. This may not be the default pose you see in the Virtual Editor. To see the initial pose of all animated SkinMesh objects in the scene, hold the [F] key pressed.

    Parameters

  • If the Working At Start option is not checked, the trail will only be emitted after the object is started by another object, like for example EventOnInput.


  • Render mode. Burn-out rendering technique blends overlapping trails together also making them look like bright plasma.


  • Color (initial/final). Click the color buttons to open the color picker.


  • Opacity (0-1). The lower the value, the more transparent the trail.


  • Frequency (trail segments per second) is the number of trail segments emitted every second.


  • Lifetime (in seconds) determines how quickly the trail will vanish.


  • Size (in meters) can be any value above 0, but keep in mind that bigger trails are slower to render.


  • Expansion speed (in meters per second) can be used to expand/shrink the trail run-time.




    • Other dialog controls

    For information about the remaining controls, please click here.


    INTERNAL PARAMETERS


    The following internal parameters can be set by using objects like Script:

  • Frequency (trail segments per second), write only
  • Opacity (between 0 and 1), write only


    • LIMITATIONS

    Trail source location on a fast moving/spinning parent object is calculated by a special prediction algorithm.

    When the parent moves on a curved path, the exact position of the source in 3d space can be very complex to calculate accurately.

    This may cause the trail source to appear slightly displaced at times.