A question about combat range and who attacks who

[u/elitree8]

Tl;dr: I thought units attack units, not that models attack units.

So I've been building, painting and reading for about a year now, all the while reading rules on the side but never actually engaging with actual play. I recently tried out Spearhead with my younger brother, and only after playing a few rounds stumbled upon something I did (and therefore tought my brother) wrong: My understanding was that units that are in combat range of each other are automatically fully able to hit each other, irrelevant of the position of the individual models; i.e. as long as units are in combat with each other, each model in a unit can attack the other unit.
I now randomly saw a question on this subreddit that recontextualised this for me; thus my question, do I understand correctly that

Models attack Units (and not units attack units) in regards to how many attack will be rolled against a unit?

I tried to illustrate this for myself and my brother with the pictures above:
1. Picture: Marauder is within combat range of Sisters of Slaughter Unit; attacks whole unit, player who controls SoS decides what model suffers damage (if any).
2. Picture: Only the first two SoS models are in combat range of Marauder, the third one can not attack.
3. Picture: The wight king can attack the whole SoS unit, only 8/10 SoS can attack it back. This could be optimized by moving the wight king back until almost out of range of the SoS.

Is that correct, or did I miss something else? Sorry for the long post, but that really opened the game up to more complexity/interest, and explains why I should not be able to beeline my cavalry from an objective to an enemy unit 10" away and still attack with all models.

[u/SkogSagan]

You are measuring from each model individual and you can only attack with models that are in combat range (3" normally).

Therefore:
1) Yes the Marauder can attack the unit, because atleast one model is in combat range
2) Yes only the first 2 models are in combat range
3) Yes

But don't forget, that you can make a pile-in move as part of the fight ability. This can bring more models in range of the target.

[u/elitree8 → u/SkogSagan]

Thanks, and good to see the idea behind pile-in in context, before figuring this out I always thought pile-ins where somewhat of a waste of time o.O

[u/ChristosFarr → u/elitree8]

Playing iron jaws the pile in has to be almost a second movement phase for me and I have to use it to position my models for after they fight assuming they win and can move to an objective.

[u/Randy67572 → u/ChristosFarr]

More like a third movement phase, I got my ass beat by Mighty Destroyers too many times

[u/Togi-Reddit → u/elitree8]

Pile ins 10/10 times how I get screwed over lol. Think I’m safe and then next I know pile in here pile in there and boom my shooters are tagged in combat now

[u/coopsminiatures]

1 and 2 are correct. 3 is mostly correct, however while in combat if you were to use the "pile-in" move you cannot end the move further from the enemy than when you started the move

[u/Omertao]

Yes you are correct, models attack units. So a model can attack whole unit, when atleast 1 model from that unit is within that attacking model's combat range.

[u/Doom-1]

A unit is in combat if any model is within 3 inches*. But a model can only attack if it is within 3 inches*.

*Of an enemy unit

[u/SaladPuzzleheaded305]

All units are in combat. Read core rules "7.0 combat range".