
For this tutorial, You will need 3D Studio Max 3 and up, a plugin called Ghost Trails and a plan as you will have to render twice (once for camera, and again for the FX). A word about Ghost Trails; No plugin has been more valuable to me than this simple, two command plugin (v.1.00). Its magic is in the fact that it behaves like a particle system although it resembles a mesh. It is truly amazing considering how simple it is. For MAX 4, 5, and 6, you can use the following link to grab Ghost Trails for your own use. It's super easy and super helpful...
click here to download! Currently, for MAXr3, you'll have to do an internet search for v1.00. The improvments in this Bullet Time Bullet Trail v.2 tutorial would not have been possible without the hard work and wicked experimentation and devotion of earlier 3D Kingdom Moderator, Trickskit. Thanks Drew. If you're one of the 40.000+ readers who suffered through Bullet Time Bullet Trail v.1, you should know that this method is also tricky but better. Where v.1 was geometry at its most confusing, v.2 is based in a particle system making it faster, more easily animated and procedural-like! V.2 is far superior but still requires planning your camera and moving bullets carefully. Once again, I remind you that you're attempting a budgetted version of Hollywood (ESC) FX. The results will be from one or two CPU's instead of a render farm; so keep your scene as light as possible when you can. And now, with few humorous asides and no B.S... 
To recreate the picture above, you need the following four objects as typed all in the Front Viewport.
- Sphere r=20 (Instancer) in Front Viewport with XForm Modifier.
Reduce Z-Axis to 40% to create the disk.
- Cylinder (Bullet) with an r=8.5 with one hieght segment but three to five cap segments. h=30
Convert to Editable Mesh, and Soft Select (use judgment) front vertex to make bullet front. 
Click to enlarge
Bring together the inner most faces on back of Bullet with Scale and leave SubObjects selected.
- PArray (Trail) and Pick the cylinder as the emitter (Use Selected SubObjects).
- Circle (GT) with r=40 and apply Ghost Trails to it as a modifier (new to your list of "More" modifiers).
Link GT to follow the 'back' (flat side) of the cylinder. << TRAIL >> - Speed .01 and Birth Rate to 1.0 and no divergence.
- Grow for 35 to 45 but no fading out. Just Life at 50 to 55. Display until 101.
- Adjust the 'Size' from 1.0 to 0.5
- Spin Axis Controls: Direction of Travel/Mblur
- Object Motion Inheritance: 0.0
- Percentage of Particles: 100%
- Uniqueness (New) Seed: Set to zero (0) Animate BULLET Locally 1000 units in 100 frames with a half way point too at 500 units (frame 50). - Check that the particle system is emitting somewhat evenly.
- Viewport Display as Ticks for now.
- Instanced geometry and select Instancer (the Sphere with XForm).
- Right click and TrackView Selected...
- Trail > Object(PArray) You will now use the following buttons: Assign Controller AND Graph View.
What you learn here will be valuable for your later, more professional projects and efforts. Identifying these means for a better Bullet Trail is what gave birth to the very idea of a v.2 tutorial. Many hypothesized a Particle System solution, only Drew thought to use the power of Controllers. **Settings may vary!** 
Highlight Size Variation and click Assign Controller.
Choose Waveform.
- Settings (Right Click Size Variation > Properties) Period: 12.5 Amplitute: 100 Phase: .3 Verticle Bias: Auto < 0.
- Move slider to frame 50 or so, Viewport Display (Under Trail's Modifier Tab) as Mesh.
- Observe full trail effect in Left Viewport. **My computer seemed to randomize the Waveform through the particles...**
**If yours does as well, follow me to the next step, otherwise skip to Materials.** 
Click to enlarge
Put Viewport Display back to Ticks from Mesh. 
Hightlight Birth Rate and click Assign Controller.
Choose Waveform again. 
- Settings are as such: Period: 25.0 Amplitude: 2.0 Phase: 0.0 Verticle Bias: Manual 4.0.
- Note that up to 6 particles are emitted in one frame...
- Return Viewport Display to Mesh and observe Left Viewport (third picture above). Stronger computers could take Manual 11.0 or even 14.0 but weaker computers will freeze **Further adjustment will be needed for most projects. Experiement with Seed, and Waveform for Birth Rate.**
**This additional controller made the Waveform for Size Variation seem more regular for BETA testers.** << MATERIALS >> - Render > Environment: Select Checker from the list.
- Click and drag this to the Material Browser in an empty slot; choose Instance and make 10x10 squares (Tile = 5.0 and 5.0).
- Select the TRAIL (PArray) and create a Reflect/Refract Material for Refraction @ 100.
- Every Nth frame (1) and Size of 150 Using Environment Map.
- Extended Parameters: Index of Refraction: 1.2
- Assign the Material to the selection (TRAIL).
- Select the Ghost Trail on the Circle (GT) linked to the cylinder (Bullet) Settings for Ghost Trail are 10 frames longer than PArray's Life!! PArray MUST have 'Life' shorter than Ghost Trail's 'Frames' so it dies INSIDE the Circle's Trail.
Also make 'Segments' 1/10th of the 'Frames.'
**Example: PArray Life=40 therefore Ghost Trail (GT) Frames=50 and Segments=5**
- Material for Ghost Trail: Diffuse is background environment...
- For now, set it to Checker (10x10) in Environment and Self-Illumination to 100.
- Opacity is Gradient Ramp where beginning is white and later is black;
- Also Angle W should be set to 90.0
- Finally, Check 2-sided, Specular level=0 and Glossiness=0
- Apply Material to selection (GT). 
What you see above: Disk face on; Disk at 45 degrees; Disk from the side.
A more complex material for the Trail would have Refraction occuring from the side of each disk and not from the face of the disk. Following is a more advanced, although flawed, Material that will come close to this property. << TRAIL MATERIAL REDUX >> Blinn Basic Parameters for Specular Highlights are:
- Specular Level: 50, for highly lighted scenes, lower this to just 5,
- Glossiness: 25.
- Refraction (100) is Falloff
- "Front : Side";
- Type=Perpendicular/Parallel;
- Direction=Local Z-Axis (scroll down the list to find that one). >>If test render shows a problem, try Local Y or Local X to fix.
- Black Color is the Environment.
- White Color is Reflect/Refract.
- Reflect/Refract is Automatic,
- Use Environment Map" with Size at 150.
- In Automatic settings, select Every Nth Frame: 1
- In the Falloff's Mix Curve you will add two points and mimic the following positions: 
Test render a frame (about frame 50) to be sure that Ghost Trail is bigger (radius) than any particle.
**Not happy with trail? Expand the trail ripples by compressing Bullet's animation keys, or extend its trip from 1000 units to something more and remember to also adjust the midpoint.** << ANIMATING >> - In a new scene, Merge the Bullet(Cylinder) (not the PArray or Circle).
- Create a camera and track the cylinder's movement.
- Remember to let the bullet/cylinder pass out of view at the end.
- Keep the camera movements simple;
- Moving too fast will confuse, not delight, the audience.
- Create lighting and a scene based on the camera's view and motion.
- Delete the Bullet (cylinder) from the scene and render through the camera as an animation.
- This animation will be used as the background for the cylinder and PArray.
TIP: Avoid letting the camera look straight at the back of the Bullet since this will break the GT fading illusion. << COMPOSITING >> - Now there's a background that's new to the first scene we made with the PArray.
- Goto the Material Browser and tell all items to look now at the animation you just made (remember that we used a Checker background, that's what we're replacing now with the animation).
- At frame 50 Render a test frame to ensure complete replacement.
- Merge the Camera from the animation scene; it should track the cylinder "automatically."
- Make no changes to the camera's movement!!
- Test a few more frames to see if you are happy with the results and then render. 
Pretty cool, huh? You should have a 'fading' bullet trail that refracts the animated background (not perfectly) and the recognizable shape of the Matrix Bullet Time Bullet Trail as well. Please use and see Comments below to discuss any issues or share extra tips. Thanks! UPDATE: Download this model! (November 29th, 2003) This tutorial was written by 3DK Admin BryanA. Edited by PiLe |
댓글을 달아 주세요