The values from the curvature of the drawn curve are taken over, but they are misinterpreted. While the keyframes are taken over correctly, the values from the curvature would have to be about 150 times larger.
The automatically generated curve is probably correct.

Good example, Matthias.

The same type of thing happens with the Brightness & Contrast FX and the Pixellation FX. There is a tiny change in numerical value as the manual curve is adjusted, but it doesn't give any significant change in the video preview. The result is always almost exactly the same as a standard Smooth Fade. It's as if a factor is wrong in the underlying calculations. So in its current form the manual curve is just redundant and very misleading. And yes, I'm starting to repeat myself 😵

Funny that you guys think that that is a bug - if it is an adjustment done by the user.

@Wolfgang S. Can you give any example, apart from Protype Titler, where the result of a manual curve is not almost identical to a standard Smooth Fade curve?

@Wolfgang S. The more I think about it the more I agree with you. Not only the curve design type between different FX just differ, but also there seems to be different kinds of curve maths inside same OFX dependend wether you use manual handles or fixed interpolation presets, which then may be not a bug in a technical sense but a poorly designed implemantation user wise.

[Ticket#2018042517010228] I'll report any reply.

@Wolfgang S. Can you give any example, apart from Protype Titler, where the result of a manual curve is not almost identical to a standard Smooth Fade curve?

Do not know what you mean by this question?

This video shows for me the first time a bug.

If you have two keyframes at the same position, and establish splin lines that move up the interpolated red curve, and the playback does not show a change between the two identical keyframes, then this IS a bug. See 0:27. Because here you would have to set another keyframe to generate what the red line Shows.

Also, that video shows OFX curves behave differently dependend on which OFX is used. The more we look into it the more strange cases occur.

@Wolfgang S. Can you give any example, apart from Protype Titler, where the result of a manual curve is not almost identical to a standard Smooth Fade curve?

Do not know what you mean by this question?

@Wolfgang S. Not really sure how I can rephrase it. Because you disagreed that there is a bug, I was hoping you could demonstrate some useful application for manual curves, where a standard Smooth Fade curve doesn't do almost exactly the same thing.

Or we can just agree to disagree for now and wait to see if Magix have a view on it.

This is the Fast Fade curve:

This is the Manual curve. It's almost identical to the Fast Fade curve:

Nick, for sure there are splin lines set in the second graph that you do not Show. Make a click to the keyframe and have a look how the splin line looks like. For sure they do not have a gradient of zero.

And that means simply that the settings are wrong if you wish to have a smooth curve.

I missed this comment earlier and I'm scratching my head over it. It is the shape of the curve that matters and not what tangents ("splin lines") create that shape. That's how Color Curves work so that's how I would expect this to work. I didn't want a smooth curve, I wanted a manual curve the same shape as a Fast Fade curve so that I could demonstrate the huge difference in how they are interpreted.

"That's how Color Curves work so that's how I would expect this to work."

But the Color Curves FX graph is a spatial definition of parameter values, while OFX curves work temporal (except of those ones with a spatial FX paramater which keyframes seem to have a spatial smoothness added in some cases).

This is the Fast Fade curve:

This is the Manual curve. It's almost identical to the Fast Fade curve:

Nick, for sure there are splin lines set in the second graph that you do not Show. Make a click to the keyframe and have a look how the splin line looks like. For sure they do not have a gradient of zero.

And that means simply that the settings are wrong if you wish to have a smooth curve.

I missed this comment earlier and I'm scratching my head over it. It is the shape of the curve that matters and not what tangents ("splin lines") create that shape. That's how Color Curves work so that's how I would expect this to work. I didn't want a smooth curve, I wanted a manual curve the same shape as a Fast Fade curve so that I could demonstrate the huge difference in how they are interpreted.

So you want the shape of the curve but are not interested in the splin lines that generate the shape?

I really have to wonder.

If someone is keen to test another oddity: Here is a project with a simple linear luma animation from black to white. Animation starts at frame # 100 and ends at frame # 300. HSL FX is used to animate the luma. And from frame # 100 to frame # 300 each frame rises the HSL "Luminance" value exactly 0.010, so it starts with "Luminance" value 0 and ends at value 2.0.

It's simple linear.
Now if you open the FX window, switch the keyframe control to the curves view, select the second keyframe at frame # 100 and change it to manual spline adjustment and same for the third keyframe at frame # 300, fun begins:
Try to recreate the linear luma rising where each frame step represents a rise of value of 0.010. Seems to be impossible by using manual splines. Curious if someone gets it anyway.
Hard to find a way to rebuild any of the given fixed interpolation presets by using manual splines. It's totally different math behind while the graph is totally misleading us.

O.k. – it's not impossible to rebuild a linear animation with manual splines. But it's totally different math and it draws a totally different curve for the same type of animation. What is linear for the fixed interpolation preset is a sinus wave for the manual splines. See here (it's based on the HSL luma animation of the project file linked in the post before):

Linear animation using the fixed "linear" interpolation preset

Linear animation using manual splines

Just to remind we talk about three or four different things meanwhile … ;)
But I still think the very base of confusion is users would not expect a temporal curve graph (what it actually is) as this is just a poor representation of the resulting FX. While all of it may be mathematical correct, it's far from being user-friendly.

So you want the shape of the curve but are not interested in the splin lines that generate the shape?

Obviously I'm interested in them because I needed to manipulate them to get the shape I wanted. But once I've got that curve shape, why do I need to have any further interest in the tangents ("splin lines")?

I really have to wonder.

I'm as baffled by your postings as you are by mine, Wolfgang. Instead of wondering, how about coming up with an example where a manual curve is of any use? I expect you won't be able to because they just don't work properly, but I'd be happy to be proved wrong.

@Marco - The example in your last comments are a perfect example of what I've been seeing. A manual curve with any "sensible" sort of shape gives very similar results to a standard Smooth Fade curve. And the effect of any adjustment to a manual curve is far less than you would expect. So you therefore need a massively exaggerated "reverse" curve, just like you've shown in the last screenshot, to correct the behaviour of the manual curve from "Smooth Fade" to "Linear Fade".

I found a previous case here: https://www.vegascreativesoftware.info/us/forum/vegas-pro-14-bug-animation-interpolation-always-linear--109744/

I wanted to try this in VP10 but whichever FX I try, I find that Manual, Split Manual, Lanes & Curves are all greyed out (previous post about it here). Anyone know why that could be?

Are these already OFX in VP10?

Are these already OFX in VP10?

No. The only native OFX that plugin I can find in it is the Stereoscopic 3D Adjust. I also have various other 3rd-party OFX that are listed in VP10, like Vision Color LUT, Yadif Deinterlace, NewBlue stuff. I'll try and do a quantifiable test if I can and compare with VP12-15. I'm wondering if the behaviour went wrong when Vegas was ported from 32-bit to 64-bit. An awful lot of stuff got broken around VP11, some of it never fixed since.

Hard to find a way to rebuild any of the given fixed interpolation presets by using manual splines. It's totally different math behind while the graph is totally misleading us.

Well it can be done approximatle, but not very easy or comfortabel.

 how about coming up with an example where a manual curve is of any use? I expect you won't be able to because they just don't work properly, but I'd be happy to be proved wrong.

If nobody works with this spline functions in Vegas, then this should be the Major Point. In other tools like Resolve the use spine functions is a central aspect. So why should it be my task to come here up with an example?

So I tested the Stereoscopic 3D Adjust FX in VP10 (32-bit) and it has the same bug with the manual curve, so it seems to have been broken ever since it was introduced.

 how about coming up with an example where a manual curve is of any use? I expect you won't be able to because they just don't work properly, but I'd be happy to be proved wrong.

If nobody works with this spline functions in Vegas, then this should be the Major Point. In other tools like Resolve the use spine functions is a central aspect...

But people do attempt to work with manual curves and then find they don't work, as evidenced by this post and that post. It's not common but it happens. So either fix the issue or remove the feature.

...So why should it be my task to come here up with an example?

To bring some factual evidence to your side of the debate instead of insinuating remarks like "I really have to wonder". Of course it's entirely up to you.

"I wanted to try this in VP10 but whichever FX I try, I find that Manual, Split Manual, Lanes & Curves are all greyed out (previous post about it here). Anyone know why that could be?"

I think the manual spline FX adjustment came with OFX.

"I wanted to try this in VP10 but whichever FX I try, I find that Manual, Split Manual, Lanes & Curves are all greyed out (previous post about it here). Anyone know why that could be?"

I think the manual spline FX adjustment came with OFX.

I agree. But it's curious that all-but-one native effects in VP10 (i.e. all the non-OFX ones) have those 4 items greyed out, instead of just not displaying them.

Yes, I'm just looking for a tool which is not a regular FX but also uses keyframing (just like Pan/Crop or Track Motion) and where splines might be available. But yet I didn't find one. It would need a different keyframe control, just like you have to switch to the curves view in OFX. It's strange this choice is visible but not available anywhere in the whole application.
Also I wonder if the spline behaviour of same OFX is different in different applications. Will test with HitFilm/Ignite later.

But people do attempt to work with manual curves and then find they don't work, as evidenced by this post and that post. It's not common but it happens. So either fix the issue or remove the feature.

I agree. Since the problem only seems purely mathematical, troubleshooting will be relatively easy. No operating systems, graphics cards, GPU, drivers etc.
One thing should be fixed at the same time with: Sometimes the handles disappear partially and can then no longer be grasped.