Bug Different scenes behave wildly differently

I'm not super experienced, but I have to think this is a problem with Unity, not something I've done.

I have 3 different scenes of a 2D platformer. Each scene has basically identical setups:
1. a basic rectangle labelled as "Ground"
2. a "player" object brought into scene from a prefab (triple checked - there are no overrides)

When I enter play mode and hit jump in each of the 3 scenes, I get wildly different results. One is what I actually designed. In another, the player goes floating way up low-grav style. In the other he only gets 2/3 of the intended height as if there's some super gravity at play.

I do not in fact use the built in gravity simulation, I just change move vectors and do it all manually. Regardless, every parameter is identical in each of the 3 scenes yet I keep getting these varying results.

Anyone able to offer some insight please, or is it actually a bug in Unity? I'm at my wit's end with this one.

 

Then debug it and see how the values are different from one scene to the next!

You must find a way to get the information you need in order to reason about what the problem is.

Once you understand what the problem is, you may begin to reason about a solution to the problem.

What is often happening in these cases is one of the following:

- the code you think is executing is not actually executing at all
- the code is executing far EARLIER or LATER than you think
- the code is executing far LESS OFTEN than you think
- the code is executing far MORE OFTEN than you think
- the code is executing on another GameObject than you think it is
- you're getting an error or warning and you haven't noticed it in the console window

To help gain more insight into your problem, I recommend liberally sprinkling

Debug.Log()

statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

- is this code even running? which parts are running? how often does it run? what order does it run in?
- what are the values of the variables involved? Are they initialized? Are the values reasonable?
- are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as

Debug.Log("Problem!",this);

If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer or iOS: https://forum.unity.com/threads/how-to-capturing-device-logs-on-ios.529920/ or this answer for Android: https://forum.unity.com/threads/how-to-capturing-device-logs-on-android.528680/

If you are working in VR, it might be useful to make your on onscreen log output, or integrate one from the asset store, so you can see what is happening as you operate your software.

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here's an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

https://forum.unity.com/threads/coroutine-missing-hint-and-error.1103197/#post-7100494

When in doubt, print it out!(tm)

Note: the

print()

function is an alias for Debug.Log() provided by the MonoBehaviour class.

 

Thank you for taking the time to write such a thorough response. I do make fairly heavy use of Debug.Log but several of the other ideas you mentioned are new to me. I have a renewed energy to go in and isolate the issue. Thanks, will update this post when I come up with something.

 

Well, I figured it out! I took your suggestion of isolating the issue by disabling other scene elements and found that the more enemies I had, the higher I could jump. After taking a close look at the jump calculations, I realized I had forgotten to multiply the gravity force by Time.deltaTime. Problem appears to be resolved.

Again, thank you very much for taking the time to help me. I will be saving this post and referring to your answer for some time to come - so much good stuff in there!

edited for typo