Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: atelieryork on 2015-10-30, 12:43:57

Title: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: atelieryork on 2015-10-30, 12:43:57
Quite a nasty bug:

Open any corona scene, set a bump map value to 1.0 in a corona material, save it in RC5, then open it again in 1.2.1 and it will have changed to 4.0.

Do the same but at 2, it will come back as 8. 4, back at 16 and so on.
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: atelieryork on 2015-10-30, 13:00:34
Interesting finding - it only does this if you have an actual map in the slot. If you set your bump to 1.0 but don't use a map, it will remain 1.0 when going from RC5 to 1.2.1. As soon as you use a map the x4 bug happens.

Oh god other things have changed too.

Absorbtion distance is changing... 0.2 changed to 0.289.

We tried everything here. So it's just the bump and absorbtion distance that are bugged.
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: atelieryork on 2015-10-30, 13:06:36
I've uploaded the max file. No maps but you shouldn't need them. floor bump_RC5.max

To replicate, simply open this same file in 1.2.1 and those 2 values will change.
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: romullus on 2015-10-30, 13:29:08
Not sure about absorbtion, but bump changing between 1.2 and 1.3 is not a bug. It's made for backward compatibility - bump strength was increased in 1.3.
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: atelieryork on 2015-10-30, 13:34:59
Not sure about absorbtion, but bump changing between 1.2 and 1.3 is not a bug. It's made for backward compatibility - bump strength was increased in 1.3.

The value gets multiplied by 4 and definitely looks very different in RC5 than how it looked at 1 in 1.2, so if it's been done for backwards compatibility then it's very problematic. Surely if someone passes you a scene in 1.3 and you open in it in 1.2.1 then it should not change values. Because if they then work on the scene in 1.2.1, save it and send it back to the other person using 1.3 the values will be all wrong again.
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: maru on 2015-10-30, 13:43:38
Quote
2. Backup your work to be 100% safe
Source: https://corona-renderer.com/blog/corona-1-3-rc1/
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: pokoy on 2015-10-30, 14:03:31
Not sure about absorbtion, but bump changing between 1.2 and 1.3 is not a bug. It's made for backward compatibility - bump strength was increased in 1.3.
Wasn't this the case when going from 1.1 to 1.2? Is this changed once again for 1.3?
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: karnak on 2015-10-30, 14:22:05
It would be helpful to keep track of these numeric changes between versions.
I'm thinking about a thread in the forum that keeps track of these multiplication factors.
Something like this:

Corona version     1.1     1.2     1.3
Refl. glossiness1??
Bump1?4
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: romullus on 2015-10-30, 14:32:02
Not sure about absorbtion, but bump changing between 1.2 and 1.3 is not a bug. It's made for backward compatibility - bump strength was increased in 1.3.
Wasn't this the case when going from 1.1 to 1.2? Is this changed once again for 1.3?
Maybe, i'm using dailies constantly, so for me it's very hard to keep track when something was changed :/

Anyway, did some quick test and it seems that indeed legacy check system gets broken once again. It affects not only bump but BRDF too. So it's urgently needs Ondra's attention.
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: atelieryork on 2015-10-30, 14:34:58
Yes it really does need to be looked at.

This isn't really an issue about "backing up" and being careful. It's also about scene sharing. Imagine my colleague is working on 1.3 and I'm still in 1.2, or visa versa. That's going to be fairly common for the next months/year while people and offices upgrade to 1.3. Every single one of those projects is going to break...
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: Ondra on 2015-10-30, 14:52:28
going back will trigger the change even though it is unnecessary, yes. We are aware of this, but it cannot be fixed now, because 1.2 is already out. In 1.3+ these situations will no longer happen - going back will not modify any values unnecessarily (but of course there could still be problems with missing maps etc)
Title: Re: Saving in RC5 opening in 1.2.1 Multiplies Bump Map value by 4x!
Post by: tallbox on 2015-10-30, 17:13:00
Quite a nasty bug:

Open any corona scene, set a bump map value to 1.0 in a corona material, save it in RC5, then open it again in 1.2.1 and it will have changed to 4.0.

Do the same but at 2, it will come back as 8. 4, back at 16 and so on.
As i said earlier i got same issue changing max versions and corona versions.