Transparency question

Transparency question

Hi guys,

I've made a sample scene here. In it I have a plane which starts off opaque Transparency 1.0 and over the course of 30 frames changes to completely transparent (0.0). This is all keyed in the f-curve editor.

What I want to know is this:

The current material behaviour in the viewport has the object getting more transparent over 30 frames HOWEVER....up to frame 7, the objects material itself seems to get lighter?

Is this as intended? Shouldn't the material colour be constant?

Also, when the object is 100% transparent, I can still see it.

Thanks
Matt

So we've been doing some digging.

Hopefully this will help clarify....

Screenshot 1 shows my poly plane with a .png texture on it (with its own alpha)
Opacity 100%
'Brightness' is 'Black'

Screenshot 2 shows the same, but with opacity at 0%. 'Brightness' is still 'Black'
Opacity does not affect anything.
Screenshot 3 shows that with opacity at 0% even the render is not correct.

Screenshot 4 shows opacity 100% but with 'brightness' set to 'white'. In the viewport the poly becomes transparent. But in the render it is STILL solid.

I need to have a way of getting keyed data to our engineers, that allows them to make transparency work in game as it does in Cheetah, but right now I cannot see how to get it working properly in cheetah.

The way I think it should work is simple. Adjusting the opacity slider should make the poly in the viewport become more/less transparent. Brightness really shouldn't affect anything. Adjusting opacity should also affect the transparency in the render.

Am I missing something, because this sure feels like a bug to me.

Thanks
Matt

Hi Matt,
yes, that was a bug. It should get brighter at the first few frames. I've fixed that and it will work properly in Cheetah3D 6.3 (sorry but that bug fix won't make it in 6.2 anymore).

That the object doesn't get completely transparent in the OpenGL preview is intended. Objects will always have a min. opacity of 0.1 so that they are still visible and therefore can be seen and selected.

Bye
Martin

Hi Martin,

We can't seem to read the transparency from the material via javascript. Is this a feature that is likely to be supported soon (if it isn't already)? For our current project we need to be able to fade in/out materials and have this data available to our engineers.

Many Thanks
Matt Thomson

Interesting question about transparencies. It sounds complicated regarding the solution, but glad Martin was able to shed some light on the problem, via an upcoming fix.

Sounds like you need the transparency object to work while in OPEN GL for a game as you suggested. Sorry I couldn't offer help, despite having knowledge of transparency tricks/fades for rendering purposes.

Its not so much that it needs to work in the viewport (although that would be ideal!)



It's that I need the keyframe data stored somewhere so when run our export script we can read it. If we can't do this then we have to find another solution, or look to other software, which I'd rather not do now, as for most other things we have cheetah workflows.

Thanks
Matt

I agree.

I stick with Cheetah 3D and try to find solutions to certain effects, or work arounds when the tools are still in development, rather than try to tackle the complexity and user unfriendliness of some of the other programs out there. Cheetah's user friendly layout helps make computer animation more fun even when it's a challenge.

I hope you're able to resolve the key frame storage issue one way or another.

Martin said:

Hi Matt,
yes, that was a bug. It should get brighter at the first few frames. I've fixed that and it will work properly in Cheetah3D 6.3 (sorry but that bug fix won't make it in 6.2 anymore).

That the object doesn't get completely transparent in the OpenGL preview is intended. Objects will always have a min. opacity of 0.1 so that they are still visible and therefore can be seen and selected.

Bye
Martin

Click to expand...

Sorry for the double post.

Hi Martin, any news on when we might expect Cheetah 3D 6.2 and what one new feature might be? Looking forward to it.

Great job with the physics by the way, they are helping out with my new project. :icon_thumbup:

lowpolymatt said:

Hi Martin,

We can't seem to read the transparency from the material via javascript. Is this a feature that is likely to be supported soon (if it isn't already)? For our current project we need to be able to fade in/out materials and have this data available to our engineers.

Click to expand...

Hi Matt,
I'm sorry but these values can't be accessed yet. But I've added them to the Javascript API. They are called

Material::reflection()
Material::transmission()

Unluckily they won't make it in v6.2 anymore which I will release very soon. But they will be in v6.3.

Bye
Martin

DarthSidious05 said:

Hi Martin, any news on when we might expect Cheetah 3D 6.2 and what one new feature might be? Looking forward to it.

Click to expand...

Probably next week. The rest is a surprise. :smile:

Bye
Martin

Hi Martin,

Is there any other way I can get the data out?

(hooking transparency of a material to the length of a bone or something? (So I can scale a bone, that data can be read, and by scaling the bone it adjusts the transparency in the scene?)

I know you're still working on 6.2, but is there a rough ETA on 6.3 with this available in the API?

Thanks
Matt

Martin said:

Probably next week. The rest is a surprise. :smile:

Bye
Martin

Click to expand...