Can someone explain the difference between using an image map (clicking on the little grey thumbnail) and using a 'layer map' ... I can see previews with the former but no the latter ... and also I'm convinced that I've created a good tga file with an alpha channel but there still seems to be some information in the transparent area ie when I apply the map to a 3d object I seem to still see something in the background ... I've also tried a PCT ...any advice please ... best ... Roger
Thanks John and Jon .... I'm still a little confused I just wonder why there are 2 methods and if one is better than another .... and Jon .... yes I'm just applying my tga as an image from a file to the topmost of the 5 boxes ... should I be applying it to the transparency box as well ? .... thanks as ever for your time ... Roger
There are two methods because layermapping allows you to map anything you can put in the AE timeline onto objects... still images, animations, even video. Because you can map precomps as well as images and movies you gain a ton of flexibility, in terms of where certain parts of the image are placed.
Image maps are normally pict or tga format. If you want to apply an image to an object like a decal, you can apply the image in the top thumbnail box as it sounds like you did. If it has a properly prepared alpha channel, you can drop the same image in the transparency thumbnail. Keep in mind the black areas of the alpha channel will be transparent and the white areas will be opaque. Gray will be semi-opaque.
Otherwise, create a black and white image for the transparency channel to behave like a mask. Black is transparent. White is opaque, as before.
It certainly does help Jon ... I read the manual and didn't appreciate that the alpha channel needed to be put in on it's own .... just to labour the point ... there therefore is no difference between using an image and a layer map ?
I'd say this about layer mapping versus image mapping. These tools are very much alike in that you can use either to apply surface attributes to objects. If all you want to do is apply an image to an object, the end result can be identical.
However, the two techniques are definitely not the same. Layermapping opens up so very many doors, because the only limit to what you apply to an object is what you can put into an AE timeline. It's definitely worth exploring the power and flexibility layermapping offers compared to image mapping.