Any thoughts on this topic or drawings, pictures or video would be great.

I was thinking if the shtf how would you go about hiding your smoke or smell from your cooking or heating fire ?

Could you burn in the ground filtering the smoke through dug out channels in the ground like filters ?

That might be hard to do, unless...
Take a day and prepare dehydrated foods and jerked meats. Might look into making boil in a bag meals, at least there will not be the food smell?
I'm hoping to make a still, use alcohol to boil your meals...
Problem solved and if not take 2 shots and rethink!

For as near a smokeless fire as possible use only the driest standing hard wood you can find and de-bark all wood since it is the bark that cause the most smoke.
Build your (small) fire if possible under a thickly canopied tree or anything that will disperse the what smoke there is.
As was previously mentioned the Dakota fire hole is the best option for concealing a fire and will burn hotter and more completely than any fire built on top of the ground.
Now as to concealing the smell of cooking. Not going to happen if you are cooking over a fire (be it well concealed and smokeless) there is going to be a smell , and a very hungry or starving person (as well as animals) will smell it a lot farther than someone who is not.
So in the event it becomes necessary to be worried about cooking odors you will want to do your cooking in the daylight hours and move to a different location for the night.If you are in a fixed location then other options may be available to you.
Solar cooking is another method with minimal odors but if you are on the move and on foot this in all likely hood will not be possible.
Baking/steaming food sealed in tin foil and or clay is another option that limits the amount of cooking odors.