I Have made animation using illustrator file in after effects in low resolution
Now, how to change illustrator file with high resolution without losing animation and size ?
Once you've rendered the animation there's nothing you can do. You need to go back into after effects and resize everything.
How complicated that will be is impossible to say. It depends on the specifics of your project and your expertise with AE.
In the future you should create with the resolution you wish to render in in mind.
You could try going to File->Scripts->Scale Composition in After Effects.
If you still have the Composition in the After Effects project, activate the Continuous Rasterization in the Layers, create a new larger Composition and put the Composition of your animation in that new one, scale it to fit the size of the new Composition that is Larger, it activates the Continuous Rasterization again in the Layer of your nested Composition and you only have to render.
thats exactly what i was looking for.
What did you end up doing? Please let us know.
Still hold with same issue..... unable fix it