Constant speed on Dolly Track

Hey guys,

I'm trying to move the camera with constant speed on a dolly track.
I managed to calculate the length of the segments between two waypoints and animate the "Path Position" value based on that.
What I noticed is that when the camera is approaching the next waypoint, it slows down a bit.
All the damping values are set to 0. Am I missing something? Is there a way to bypass the easing?

Thanks for your help.

 

Hi Gregoryl,

Thanks for your quick reply!
See my test script below.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using Cinemachine;
5. using UnityEditor;
6.  
7. public class MoveCameraTest : MonoBehaviour {
8.  
9.     public CinemachineVirtualCamera virtualCamera;
10.     public CinemachinePath path;
11.     public AnimationCurve curve;
12.     public float runningTime;
13.     public float totalDuration;
14.     public float currentPercentage;
15.  
16.     private CinemachineTrackedDolly dolly;
17.     private float pathLength;
18.  
19.     private float[] pointPercentages;
20.  
21.     void Start(){
22.         dolly = virtualCamera.GetCinemachineComponent<CinemachineTrackedDolly> ();
23.  
24.         pointPercentages = new float[path.m_Waypoints.Length + 1];
25.         pointPercentages [0] = 0;
26.         Keyframe keyframe = new Keyframe (0, 0);
27.         curve.AddKey (keyframe);
28.  
29.         float length = 0;
30.         float step = 1f / path.m_Appearance.steps;
31.  
32.         //Calculate total length of path
33.         for (float t = path.MinPos + step; t <= path.MaxPos + step / 2; t += step) {
34.             Vector3 prev = path.EvaluatePosition(t-step);
35.             Vector3 p = path.EvaluatePosition(t);
36.             length += Vector3.Distance (prev, p);
37.         }
38.  
39.         pathLength = length;
40.  
41.         float partialLength = 0;
42.         int counter = 0;
43.         int currentStep = 0;
44.         float currentPercentage = 0;
45.  
46.         //Build speed curve
47.         for (float t = path.MinPos + step; t <= path.MaxPos + step / 2; t += step) {
48.             Vector3 prev = path.EvaluatePosition(t-step);
49.             Vector3 p = path.EvaluatePosition(t);
50.             partialLength += Vector3.Distance (prev, p);
51.             counter++;
52.             if (path.m_Appearance.steps == counter) {
53.                 currentStep = Mathf.RoundToInt (t);
54.                 currentPercentage = (partialLength / pathLength);
55.                 pointPercentages [currentStep] = currentPercentage;
56.                 counter = 0;
57.                 keyframe = new Keyframe (currentPercentage, currentStep);
58.                 curve.AddKey (keyframe);
59.             }
60.         }
61.  
62.         for (int i = 0; i < curve.keys.Length; i++){
63.             AnimationUtility.SetKeyLeftTangentMode (curve, i, AnimationUtility.TangentMode.Linear);
64.             AnimationUtility.SetKeyRightTangentMode (curve, i, AnimationUtility.TangentMode.Linear);
65.         }
66.     }
67.  
68.     void Update(){
69.         runningTime += Time.deltaTime;
70.         currentPercentage = runningTime / totalDuration;
71.  
72.         if (runningTime >= totalDuration) {
73.             runningTime -= totalDuration;
74.         }
75.         dolly.m_PathPosition = getPathPositionFromPercentage (currentPercentage);
76.     }
77.  
78.     float getPathPositionFromPercentage(float perc){
79.         return curve.Evaluate(perc);
80.     }
81. }
82.  

 

Hi Gregoryl,
Great, your solution works fine. I can now move the camera with constant speed!
Thanks a lot!

 

Is there an updated version of this code for Unity version 2018.3.12f1? I'm looking for some way to have the camera move with constant speed on the dolly track. I'm just learning to include custom code in my projects but when I used the script above, it had problems with:

SamplePath(path.m_Appearance.steps); // TODO: decouple numSteps from appearance setting

 

Thank you. I will try it out.

 

Thanks Gregory, your suggestion worked like a charm. Previously, I had created the Cinemachine Dolly Camera with Track, and it didn't have the option for the constant speed. It was like being on a roller coaster; fast on turns and going down. This motion was disorienting for VR-type apps and recordings. Using your suggestion, I created the Dolly Track with Cart, I deleted the new Dolly Track (I already had a Dolly Track created), and kept just the Dolly Cart. The script for the Dolly Cart had the Speed variable that I adjusted to get the speed just right. I set the Path to the previously created Dolly Track and Added the Component for The Cinemachine Virtual Camera (DoNothing vcam). Viola! Does what I wanted it to do. Glad to have found this thread from a few years back how Unity has evolved the product to include this functionality out of the box.

I'd like to enhance my project with a small drone flying directly in front of the DollyCart and was trying to figure out whether there's a way for an asset to be pathed to the DollyCart, but it seems like DollyCarts and DollyTracks are just for the vcams.

 

Very cool. Added this script (component) to the DollyCart and added my Drone GameObject as the Font Object. Working great. I'm going to have a lot of fun creating Dolly Tracks and Dolly Carts. Thanks again Gregory for the quick response.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class MovewithCamera : MonoBehaviour
5. {
6.  
7. public GameObject frontObject;
8. public float distance;
9.  
10. void LateUpdate()
11. {
12.     frontObject.transform.position =  this.gameObject.transform.position  + this.gameObject.transform.forward * distance;
13.     frontObject.transform.rotation =    new Quaternion(0.0f, this.gameObject.transform.rotation.y, 0.0f, this.gameObject.transform.rotation.w);
14.     }
15. }
16.  

 

OMG. I disabled the script, threw the gameobject below the DollyCart...held my breath, and pressed Play. It worked! I'm just blown away by what Unity can do.



Thank you very much.

 

How do I change speed to slower on the dolly track? (Not cart) @Gregoryl

 

How fast the camera travels on the track.. how to change speed sir?

 

Yes! I used a cart instead, works good... But the virtual camera noise profiles, I cant create new because create is greyed out, and I cant duplicate a preset nothing happends, and I when I mark a noise profile, I can click "gearwheel" or edit...? why have you guys locked it ?

 

Latest from package manager... really weird... Also I build with no errors, still as soon as I run it, it crash (in build)

 

Cinemachine 2.2 with Unity 2019.2.9f1

 

I downloaded it from the package manager... Is there also 2,2 there? Maybe i didnt select latest verision..

 

Oh I will!

 

Seems 234 actually was installed...

 

Dont want to do that so.. created a new scene and copied over stuff from the other scene and now it works so I dont know lol.

 

Hello @Gregoryl ! Everything is working great, Im just a bit confused when it comes to multiple cams... I have one camera now , wich I want to be the main camera wich is travelling on a trach.. its a dolly cart... And I have different locations wich I want to also be shown with a different cam.... How can I achieve this ? What do I need to animate ? I want to use timeline..

 

Yes Thanks! I cant find a blending option, and I dont mean blend 2 cameras ... I mean when a camera becomes active so it fades in the image and then out when the camera change.. So the image dont pop in and out.. smooooth fade in, like black first and you start to see the clear image like in 2 secs.

 

Hello,

Recently I tested with cinemachine and it's really great, and more easier than I expected.

However, I want to use cinemachine auto dolly for VR game, and the smooth path is really a headache for VR when stop the camera with smooth velocity.

I see in this post that we can use Dolly Cart fot constant velocity, but it's not the same that auto dolly.

¿Some help to implement constant velocity with autoo dolly?

Thank you very much, regards.

 

You saved my life man ! It seems I also was using the "old" way, have been searching for a week and then I found your post. So easy to setup and works without a flaw, thanks !

 

When I assign the cart to my track, it moves at a constant speed which is good but it doesn't pivot or rotate with the track like the virtual camera does. What should I do to get it to move at a constant speed while being able to roll and rotate with the track?

 

Directly parenting the object in the hierarchy seemed to work. I was trying to parent the object through the script which was mainly my problem.