These "normally unscrappable" objects, does that refer to objects that are only scrappable in Vanilla FO (ie, no Place Everywhere)? I ask because kinggath himself made a reply
here in direct response to a question about contest plans stating that we "can use the Insert key from Place Everywhere to scrap more things" as long as we don't break precombines.
Please clarify: what is a "normally unscrappable" object and what is the official stance on using the extra object selection in Place Everywhere?
Thanks.
Oh good. This is my area of expertise.
OK, so this is going to be a little bit complicated - I am going to attempt to simplify it. In Fallout 4 there is a set list of objects that can be scrapped. Anything not in this list is unscrappable. To make the game run at an acceptable speed, all of these are combined together into two data objects called previs (what can we see?) and precombines (what's here that we can't scrap). These two systems are essential to make the game perform well. Precombines allows the game to draw lots of objects together. This is fast. Scrap mods (excluding Raze my settlement / Clean my settlement*) disable both of these systems in settlements. They also expand the list of objects that you can scrap. The downside is now that the game must draw each and every object, in a 5 cell by 5 cell grid around you. There are many, many objects that can go into what looks like a simple model. Drawing them one by one makes things very slow.
Following along so far. Now, sometimes when making a settlement, you might not want the player to be able to delete something that they normally could. To do this, you would use a much smaller list of objects that can be scrapped when making previs and precombines. Lets get a specific example.
Oil Lamps are something that is normally scrapable. Go to almost any settlement and you can scrap them. However, in Sanctuary, for story purposes, there is an Oil Lamp that you can not scrap normally. Of course you could install a scrap mod - but that just broke your precombines, your previs, and now your game thinks 20fps is a good rate. Sometimes the objects are unscrappable because they are hiding holes in the landscape.
Now, remember when I said Oil Lamps are normally scrappable, but in Sanctuary they aren't? Activating Extra Object Selection in Place Everywhere effectively replaces the list of objects that can be scrapped in a settlement, with the current load order list of scrapable objects. Suddenly that stubborn Oil Lamp in Sanctuary is now scrappable. The light source however is not. Even if you scrap that Oil Lamp, it will still shine there. That is how Extra Object Selection works. Now, if anything at all changes that list (scrap mods, settlement mods, extra buildable object mods), Extra Object Selection will let you scrap those objects too. This is very bad if one of those objects is part of the precombines and previs. You get tears open into the void beneath the landscape, you get flickering ghost objects, you get NPC pathing problems - and your city plan will not work for other users unless they have the exact same scrap/settlement/building mod installed.
So, in a city plan competition profile, you shouldn't be using any scrap, settlement or build mods at all. This will ensure that Place Everythere should not let you scrap things you shouldn't.
Ahh, a hostile NPC. We can't usually scrap these, or get rid of their preplaced bodies. (These bloatflies corpses will despawn once the settlement is unloaded - but others like the dead Brahmin at Taffington will not.)
Place Everywhere Extra Object Selection to the rescue - now we can scrap that bloatfly. Now, admittedly scrapping a bloatfly isn't useful. However turrets are NPCs, so if you have taken over a settlement that has turrets that you had to destroy, Place Everywhere Extra Object Selection will allow you to scrap them. That's really handy.
Now the official stance is that it is technically allowed, but if you break the settlement with it, your entry is no longer valid. Kinggath says as much in his answer.
My advice is simple. Don't use it. Scrap as much as you can without using it. It is much easier to bury unscrappable objects in landscaping then it is to make sure that that you aren't accidently scrapping something important.
* Raze my settlement / Clean my settlement work a little bit differently. Essentially they give a transparent texture to all the objects that they "remove", then they put a replacement scrapable version of that object in it's place. This allows you to "scrap" those objects. If you remove them from a game, the "scrapped" objects come back.