Blender GIS: lighting and rendering

hi welcome back so in the previous videos we focused on setting up the scene uh by importing and getting our data visualized uh in this video we're gonna focus on lighting and rendering rendering is the process of making 2d images of your 3d visualizations that you can use in publications or online or wherever to share the results of your research or just to impress people so let's get started all right lighting which is of course the process of adding light to your scene lights can be global lighting the entire scene or they can be local lighting a certain part sometimes you want to focus the attention of your viewer to certain parts of the landscape so you can add different kinds of light in order to help you with this process so in blender you add lights by going to the add menu or shift a and then go to light and then there are four types of light point sun spot and area so point lights are like this one they are basically light bulbs what that we also use at home i positioned here a series of point lights and to light up the valley another type of flight is the spotlight a spotlight is generally not used that much for landscape visualization but it gives an interesting effect as as if it's a search light another light that is perhaps more useful is the area light the area light is a basically a square plane that lights an entire area also very useful to highlight certain features of your landscape in this video we're gonna work mostly with the sunlight because this is generally the most useful uh one for us but if you finish this tutorial then you are free to experiment with all the other lights as well so we start with hitting shift a and then go to light and add sun depending on where your 3d cursor is uh the sun will appear on this location we can drag the sun up to above the terrain so we have it in a convenient position to manipulate and this little yellow ball beneath the sun is used to change the direction of the sun you can also change the direction of the sun with the rotation tool alright however you don't see any effect yet and that is because we are still in the preview mode which uses this kind of default lighting we can however turn on scene lights in this case and you see that there is a tiny effect visible already making it look better we can turn down the strength of this lighting to see it even better and then we can go with the select tool we select the sun and then we go to the sun properties on the right and then we can increase the strength of the sun so this constraint increased it also increases the contracts contrast of your digital elevation model however you may see that there is actually no shadows cast by these objects over here and that is because of a setting in the sunlight if we go here back to the sun settings uh cast shadow is on and make sure now that you are in ev rendering engine because then otherwise if you're in cycles the setting that i want you to change does not appear so in ev rendering engine you turn on shadow it still doesn't do anything however you go here to cascading shadow map so basically what this does with max distance it uh it defines the area around the sun in which shadows are actually computed and as this is quite a large landscape and the sun is high above it no object is near to the near enough to the sun like within a distance of 200 meters to cast a shadow so if we increase this distance to for instance two kilometers you can see that the object start casting shadows better still increase this value to 20 thousand to twenty kilometers and now you see that it actually works for all the objects at any camera position uh this is also important to create shading on the hills in fact but the eevee rendering engine is actually not very accurate one and the best results are generally gotten with the cycles rendering engine even though it visualizes slower in the viewport the results can be stunning if you are rendering in cycles so for the next steps we're gonna expand on our rendering and lighting skills a little bit in the cycles engine so when you switch engine you see nothing really happens that is because cycles is only functional when the rendered when the shading viewport shading is set to rendered and set to rendered it will use the cycles engine and as you all notice it will take a while to compute this image but you can also already see even though this is not a fully computed image that the results are better also because i have already added here a sky texture and i will tell you as well how to do this so you will find the settings for the sky in the world properties panel on the right it is a globe and you will see here below surface there there's a background surface and the background surface is a sky texture in your cases sky texture is not loaded so it's probably something like this and there is the background that you can change the color of and the strength of the ambient lighting but to add a sky texture we need to click here on the color and we want the color to be defined by a sky texture and in this case uh as a sky texture the nichita sky texture is loaded as you can see the scene is now too bright first we have to turn off our own sun because there are now two suns in effect there is the sun that is created by nishita wherever that sun is probably we have to turn down the intensity well we first turn down the strength of the of general lighting and here you can already see that the sun starts to appear so connection well keep this in at one for the time being so the nishita sky texture is actually three of one of three different types of sky textures and in fact uh it is the most convincing realistic uh one that allows you also to change the most uh settings so the first setting you can change the size of the sun and actually the size of the sun depends on the distance to the earth of course the base setting is quite a good setting for sun's hype in the sky the sun intensity is of course the brightness of the sun so what else do we have we have the sun elevation uh the sun elevation uh basically is the elevation of the sun in vertical axis so a high elevation means it's high up in the sky and a low elevation is near to the horizon you can create very pretty sunset landscapes with this one now it's below and what else do we have we have the sun rotation which is the rotation or the movement on the horizontal axis the altitude is not the altitude of the sun itself with the altitude of the like this the base altitude of the world and yeah the higher you get the higher you get up you get in the atmosphere and i think this is in kilometers so we're now 33 kilometers we're almost in our space how far can we go 60 um so better keep this to a realistic number like 600 meters um air is uh air dust and ozone are all three atmospheric effects the amount of air the amount of dust which creates some hazy effect and the ozone creates bluer skies and with the strength you can of course increase the strength or decrease strength of the atmospheric light so the last thing i'd like to discuss with you is how to make a render with a custom camera um custom cameras give you much better rendering visuals than a simple viewport render image which is not even a possibility when you are in the cycles render engine so um to make a custom camera the usual approach is to first go into position that you like um in this way we have a good overview of the entire territory with the sides uh the area in the mountain and the coastal plain in front of it so this seems like a nice view so we need to add a camera because we don't have a camera yet so we do shift a and then add camera and the camera is added again to the location of the 3d cursor and it happens to be created also inside the site that's not very convenient there's a camera over here so i select the camera and hit m and i make a new collection for the camera and i call it camera so the camera has its own collection and now the camera has to move to the viewpoint uh to the current viewpoint and to do this you first select the camera and then you hit view and you go to align view align active camera to view and now we don't see anything at all by the way this only works when the camera is the active camera currently we only have one camera in the scene but if you have multiple cameras in the scene and then there's only one camera a active camera and you set this in the scene settings and then camera over here this is the active camera and if you have more cameras in the scene there's a list of cameras that you can select from anyway we don't see anything that is because of a camera setting as you can see the camera's view is clipped from 10 centimeters to a thousand meters so a thousand meters is not far enough to see this entire area in fact it is not even far enough to see anything so we change this to uh 20 000 meters 20 kilometers and now we see enough all right uh the camera has a different aspect ratio than the view i had so um one way to adjust this is in the resolution so we can change the resolution of the y to make it a higher and another thing is we can change the camera's focal length and focal length is basically what gives your angle of view now you also might want to rotate the camera a little bit you can do this from the perspective of like the camera view if you're not in camera view and now the camera is too small to see i get the camera and there is some settings somewhere that the viewport display so we make it 50 meters so it's uh no it's not even a margin of 200 meters all right here we have our camera so the camera's rotation we hit local so now with the local transform set we can change the angle of the camera however it is better in fact to do this from the perspective of the camera itself while we're looking through the lens now the camera is gone where's the camera okay it's over here okay so i hit zero to go into camera view again and i see that i have rotated too much so how do you rotate so basically with r you rotate the camera and if you want to rotate uh around its local axis we have local s transform orientation on rotate x and with x i will rotate in a way that i can use it to change the vertical angle of the camera so something like this seems nice enough and then there is in render settings besides the resolution you can change you have to do this in render settings of course you change your rendering the device if you have a good gpu so graphics processor you can better render on the on the gpu but otherwise select your cpu as rendering device and then there is the option of sampling so sampling is the number of samples light samples it takes the more the more accurate and fine your result the lower the more grainy your result so besides uh the sampling of the light uh we can also turn on denoising and that's a function that came originally recently to blender in the past we had to crank up the render samples to a higher level when we had a noisy image as a result but that also meant that the computation times became significantly longer you could easily wait for hours to have a finished render however with the denoising which is a dinosaur that is supported by an a i algorithm it can create a noise free picture with relatively low render samples so we can turn this down to 64 and i think we will get a good image together with the denoiser other functions uh there's many other functions but we won't discuss this now this goes too far so to create your final render there is one other thing that we have to mind and that is to make sure that this will render on the right resolution so as you can see here in the modifier panel the subdivision levels are set for the viewport on 5 but not yet for the vendor so we make sure that this is also on five and another thing that we may need to heat yes so even though i made these invisible they will still be visible in the render because they are just invisible in the viewport but that doesn't mean they are invisible in the render itself so how to make them invisible and render well one way is to select them and just move them out of the camera but i want to show you the the proper way to do this and that is to activate one additional so-called restriction toggle this one the camera over here and then i get another restriction toggle and by hitting the camera on the group on the collection of symbology takes it out of any renders and we should do the same with the sun because otherwise we will the sun will be used in the computation of the image and it will create an too bright picture so deactivate the sun as well i think we're now set to go go to render and then render image and now the waiting can start depending on the speed this the power of your computer so the rendered image is finished to save it go to image and save you can save it as a png any kind of image format that is commonly used and then we save it whether this image has any analytical value is probably doubtful but nevertheless it is an interesting picture so this is the end of this video i will see you back in the next video

Channel: 4D Research Lab

Views: 2,229

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Id: 8FSE7TnCTH8

Length: 22min 46sec (1366 seconds)

Published: Fri Oct 23 2020