Sometimes when I'm walking through a dungeon in game, I'll see blood on the floor by a torture rack or in a cage. This blood was placed there by the devs to give the environment some personality; it was NOT there due to combat, etc.

Anyway, my question is, how would I go about adding blood like this to my dungeons? I feel like it really enhances the scene.

look for "DecalBloodSpray" in the object window

Just to elaborate, since it may not be blatantly obvious to all how to use those objects; it's a marker of an arrow. It applies the blood decal to the surface it's pointed at, so simple point it at the wall or ground from about 5 ft away and it will blanket anything below it with blood. It's SO much better than the flat decals we had to handplace in previous games because it's faster, and it applies it as a directional shader, meaning all parts of even curved surfaces get covered, instead of the one flat plane.

Thanks guys! I don't know how I passed over that when I searched for 'blood' in the filter of the object window?? And thank you for clarifying how to use the arrow marker, I did not know that was how it was done!

Alright I got another question for you guys. When I drag the decal into my render window it just puts the decal in a seemingly random place, I never have a chance to adjust the arrow??

It randomly picks from like 4 or 5 decals, but it should place them where it's pointing. Also make sure that depth biasing is on (View, Toggle Depth Biasing, I think) or it wont render properly.

Every time you move the arrow (Or ANY other object in the render window for that matter) it would re-place the decal. Not great if you want very specific results, but great if you want to cover a pile of bodies in blood.