Lobo is right that more samples = better pic/ less firefly's BUT bad materials and/or lighting and no matter how high the samples it wont look better check all settings .....watch lots of tuts ..........and if you have to CHEAT ;-) PBR maybe the new kid on the block but a good old fashioned cheat can save hours

ps to get a transparent background on a cycles render ...on render settings scroll down to film and tick the transparent box have fun

you could have used the skin modifier or convert to curves and use a bevel.....just ideas lol

for the arches use curves for main shape then another curve to use as a bevel obj then u can have the fancy shapes of the stone work can use a third curve as a taper obj .....big thick base to arch and getting thinner as they get higher and if you don't like drawing curves in blender ..........do drawing in inkscape (other) export as svg and import to blender

hope that's given you some ideas

lol long time since I used them brushes ;-) ....if the same ones I have is about 10 images so could make an animated brush, if only one image then try using warp(liquefy) suggesting the paint way as a stress-free quicker way then a smoke sim

in blender load a plane (anything) then go to object on bottom menu an pick quick effects/smoke.........that will automatically load a domain and set smoke.stuff then hit play on timeline .........you will get a nice "nuclear" mushroom of thick smoke.......now its time to look at the settings ....is lots blender guru has some good tuts on smoke but is lots on youtube too once you got it lookin ok then you need to bake it (you need to save file BEFORE baking but good idea anyway just in case blender crashes ) hope that helps

make a nice stained glass window !! you gonna make the rest of church mate ?

is possible ......load pic to a plane (add a little emission to pic for a backlight ) an set up smoke sim just in front add a wind/vortex or other force to make pretty swirls and stuff depending (on you and comp) can take 20 mins to a full day !! to get a pic u like

am sure theres free smoke brushes out there and then theres paint programs that help a lot with this type of stuff take about 10 mins

I love blenders sims but they take a lot of setting up ...........then time to run ..........then the tweaks and run again

just saying lol ..........need any help yell out but is lots of tuts on you tube

nice to know some one cares ;-) but is an add on for blender ......lets you build your model in blender link to thread at BA I hope that's allowed https://blenderartists.org/forum/showthread.php?391401-Addon-Manuel-Bastioni-Lab-turns-Blender-in-a-laboratory-for-3d-humanoids-creation

u don't need an hdri or panorama for a single image

just use any image on a plane and scale to fit camera view

hang on ............I not messed with evee yet ............so but a mix shader with one input is on or off

damn never had time to want my popcorn !!

looking good ............thought the rain a bit heavy .........but after watching Houston I not too sure ;-)

hope they finish it

remember a tut for pillows/balloons that used the cloth sim make shape an set Collison to silly numbers worked on most shapes ...........but blow to hard an balloon bursts lol

at 5 mins each worth a look

one thing I do know is I never too old to learn a new trick ;-)

blender can do smoke ........but not (at the mo ) multi coloured or constrained to a shape maybe other programs that can ( how deep is your wallet lol )

maybe with animated texture maps ~ transparency maps ...... you can do it ......depends

looks like fun .........will have a play with this

thanks for link ..........nice price too ;-)

not too sure a blacksmith would love u !! (for knife) love the usb stick (ur design or u seen one ?) looks nice an easy to pop on my keyring

have to go looking for your tuts now ;-) hope u made loads