Fading Alpha Mapped Objects

(Reno) #1

I was here a few days ago with a similar problem, but I am now able to explain my predicament a bit better.

Basically, I got a few Alpha mapped planes that I need to fade in and out in the render. I don’t know how to do this, mainly because the alpha setting is already at 0.00. Any ideas? I could use the Sequence editor, and fade them like that, but I can’t get my Alpha mapped images to overlay on the video rendered background.

So either way I’m stuck, unless Im doing the alpha mapping wrong. I just turn on ZTransp. Put the alpha slider to 0, and check “Alpha” on the Map To section. ( I also UV Map the plan and get the texture on there with Alpha+Copy Draw Mode in face edit. )


(Vertex Pusher) #2

With one your plane selected go to the Shading context (F5) in the Buttons window and go to the default Material buttons . Now hit “I” in the Buttons window . An “Insert Key” context menu will appear . Select Alpha .

Split an area and turn that into an IPO window and change to the Material IPO type (like I showed you a few posts ago) . You should now see a flat line Alpha IPO curve . It should be at 0.0 if like you said you have set the material alpha to zero .

To make things fade in and out just press Ctrl down while clicking in the IPO window with the LMB . this will add keys to your curve . Anything above 0.0 (invisible) will start to fade in with the maximum value being 1.0 (full alpha) . By just adding three keys which form a bell curve you will get the fade in/out effect (or more if you need them) by having a key start at 0.0 and then another at 1.0 then the final fade out key at 0.0 again .

To edit the curve keys/control points directly just hit Tab and bezier handles will appear and you can move them individually .

Now just do this for each plane and stagger each bell curve along the timeline by inserting the keyframes so that they fade in/out according to your preferences …

If you want more detail goe here : http://wiki.blender.org/index.php/Manual/Ipo_Types and read the next few sections …


(Fligh) #3

You need to keyframe Alpha = 1 at frame 1 for the first plane and Alpha = 0 at say frame 10. Then for plane 2 Alpha = 0 at frame 1, Alpha = 1 at frame 8 so it fades in by frame 10, then Alpha = 0 again at frame 20.

Or you can just key all frames zero at frame 1, 1 at frame 10 and zero again at frame 20. Then in the IPO Editor drag their respective IPO’s to the right manually so they fade in and out sequentially.

Ha ha, snap again VP!



(Atom) #4

Thanks a lot!

I did not realize you could use the I key in the other windows!


(Reno) #5

I get the key frame parts, its just that when alpha is at 0, the alpha mapped object is there with all the transparent parts gone. When its at Alpha 1. The alpha mapped object has all its white parts there and looks terrible.


(Albinal) #6

CD38 answered this in your other post:

Try animating the material’s Var or DefVar IPOs from 1 to zero. You may have to remove specularity as well.


(Reno) #7

Thanks everyone, I got it working. Especially CD38, that really works, thank you.