Can't figure out why my animation/character goes into muscle test pose when I hit play

I have tried various different tutorials (3rd day of learning) to try and use animation blend trees using assets from the assets store. Even tried using the Ethan model that comes with the standard assets set.

My problem is that everytime I set it all as up as I'm supposed to and hit play, instead of going into the idle pose, my character drops through the terrain/plain to his/her waist and goes into the curled up muscle test pose.

I've tried many different models/avatars/animations and it's always the same result. I've googled this extensively and all the solutions I have found just don't seem to work for me.

https://answers.unity.com/questions/398465/character-falls-thru-to-his-waist.html - this is a very old thread explaining my issue and it also contains the solution most people have said to try but it doesn't work.

I've been at this for almost 12 hours now and I would very much appreciate some help with this. please :-(

 

This commonly happens because the avatar of the animation is not set up as humanoid - and/or does not accurately match the avatar of the humanoid rig for the character you are using.
Also - Ethan by default does not match the humanoid structure - so there might be some issues with that if he is not properly aligned with the humanoid rig set up.
Consider - if you haven't already - reviewing the learning/training material in the learn section of this site - in the animation section. You are missing some Unity essential animation/mecanim knowledge which will clear up why this is happening.

 

Sorry for the late reply.

In the end I went through and built my own 3d model with its own rigs and animation. thought that would give me an insight into whats going on in the background and its all a lot clearer now.

I think i tried to jump before i could crawl LOL

thanks for taking the time to reply to this. much appreciated.

 

It happened to me as well today, and I found out that the reason was, I didn't have an idle animation clip assigned on the idle node in the animator. That's all. Still confusing that it goes on the muscle setup pose instead of remaining on the pose it was imported with.