Editing/creating 3D banners requires that you use 3D editing software that supports importing/exporting OBJ files. There are free programs like Blender I think. But I have no experience using them. I personally use 3DS Max. But it's not free. Though I think gmax might work. Don't recall if gmax could export obj files or not.
What you do need is an existing banner as a reference point. Rename banner.bin to banner.bnr. Then extract the cgfx file from it using 3DSExplorer.
Then use EveryFileExplorer to open the cgfx file. You can then export the model to use as a reference point and to make sure you make things at the correct scale.
Then once you export the edited model from your 3D modeling program of choice make sure texture paths are correct in the MTL file. Also make sure all edges are visible prior to export because if any are hidden you might end up with missing faces once imported. Also note that alpha blending on textures for 3D models is not currently supported in EveryFileExplorer, so new CGFX files won't have working alpha on textures. So you'll have to work around that.
Then use EveryFileExplorer to create a new cgfx file (you currently can't modify an existing one) from an OBJ file. Once you have that you can use bannertool to build the banner from that cgfx file.
Once you have your files ready. You can use a command like this to make bannertool build a banner using a CGFX file instead of a SMDH (which only builds 2D banners):
Code:
bannertool makebanner -ci ExampleGraphix.cgfx -a ExampleBannerSound.wav -o banner.bin
(replace example file names with those you are using in your project)
If you already have a wav file converted to CWAV (not entirely the same as BCWAV though. Keep that in mind), then you can use -ca in place of -a to define your banner sound. I'd recommend something in the 22khz or below range for your banner sound. There's a limit to how large the overall banner will be. If you have a really complex model, you might be more limited with how large the banner sound can be before banner sound playback doesn't work. Overall I think your banner file should not exceed 400 to 500 KB in size once built. Anything larger and you will run into problems.
Also a model that's too complex will not display at all when you select it on Home Menu. I haven't really tried to pin down what the exact limit is. Try to minimize the texture file size and keep the poly count below 2000 and you should be fine.
EveryFileExplorer doesn't yet support material animations/skeleton animations. So 3D banners built this way will always do the default spin in place animation. Keep that in mind.