grammar - "which" with non-noun-phrase antecedent

I became a little unsure regarding to grammar while writing a sentence that, "... will either pass through the top-right or bottom-left corner, during which ...", in which case "which" has an implied antecedent of "passing through". I believe this sentence is clear enough, but wonder whether such usage of "which" may be disapproved in formal or academic writing.

more examples:
"He resigned that post, after which he engaged in ranching."
"He died of cancer, which is what I predicted"

Answer

In the first case, use two sentences; figuring out the geometry has used up this one.

• .. will pass through either the top-right or the bottom-left corner. During this transition, ...
  (also, move either closer to the disjunction, and repeat the article to clarify it)

"Such usage of which" is not "frowned on"; but it does require a lot of interpretation by the reader.
What passes for good writing mostly is just not loading too much information into one sentence.
I.e, this is not a grammatical problem -- the relative clause is well-formed -- but a writing problem.

As can be seen in the other two examples

• 
  

  He resigned that post, after which he engaged in ranching.

  
  


• 
  

  He died of cancer, which is what I predicted.

  
  

a relative clause referring to a prior clause is perfectly grammatical. Even a preferred choice, provided one doesn't expect a simple structure to do all the heavy lifting involved in description.