In this lesson video we are going to discuss about surface smoothing. By default, when you create a 3d object in blender, the object will have a flat shedding mode. If you create a new UV sphere For example, this is what you will get, you can see all of the individual faces clearly. Another example is cylinder. You can also see the individual faces at the side of the cylinder. Now when doing 3d modeling this flat shading is perfect because we can see the geometric clearly, but when you need to render it, mostly you want the shading to look smooth.

In Blender we can switch between flat and smooth shading per object basis. To do that, first you need to select the object for example this sphere, then right click and then choose shade smooth in here. Notice the sphere now looks smooth. If you want to turn it back to flap shedding more You can right click again and then choose shade flat here. Another method is by going to the Object menu up here, you can see the shape smooth and assured flat options in here also. Okay, now switching between these two modes will not alter the geometry at all, the geometry is exactly the same.

Blender only changes how shaders are being calculated and rendered throughout the surface of the object. Okay, smoothing a sphere is nice, but what about other objects such as cylinder for example, if we select the cylinder, and then to the smooth shading mode, the cylinder looks awfully wrong. The site should look smooth, but this ages which is the border between the sides area and the cap area should not be smooth at all. To fix this issue, you can do this either automatically or manually. Let's see how to fix this using the automatic way and then later using the menu ways, the automatic way to fix the smoothing behavior is by using the auto smooth parameter. To do this, first you need to make sure the object is selected, then go to the properties editor and then open the object data panel, which is this tab here with a triangle like I can in here, you will find normals section and inside it, you can see the auto smooth option, turn this option on and right away we can see the cylinder looks so much better.

What this auto smooth option does is applying automatic smoothing on adjacent faces. If the angle between those faces is below this angle value, otherwise, the flat shading will be used instead, because the face at the cylinder cap forms a 90 degree angle with the faces at the side and of course, 90 degrees is higher than this 30 degree threshold we have in here. There is why the ages at this coordinate Use flat shading instead of smooth shading. If we drag this angle threshold down, we will get all flat shading eventually. And if we drag this value up until passing the 90 degree threshold, we will get this ugly over a smooth surface. Again, let's change this back to 30 degree, which is the default.

Now something you need to keep in mind is that this auto smooth checkbox, and also this angle threshold value will only work if you set the object's shedding type to smooth. If you set it to flat mode, then the object will always display sharp edges no matter what Okay, so just make sure you set the shading style to smooth first before using this auto smooth option. The manual way to control surface smoothing is by using the edge sharpness properties. Although this method is not as easy as the auto smooth option, it gives you free Eyes control on which ages you want to make them sharp and which ages you want to make them smooth. Through this you need to be in the edit mode and then activate the age mode. For example, let's say you want to make these ages to be sharp.

First select these three ages, right click and then choose Mark sharp here. If we click on empty space to deselect all we can see that vendor adds this cyan color to indicate sharp edges. We can see the effect better if we press tab to go back to the object mode. Because in the object mode, the shop sign color overlays are hidden. We can see these ages now look sharp because Blender does not smooth out the shading transition in this area. If we go back to the Edit Mode, we can see the cyan colored overlays again on these ages.

Personally, I prefer to have these colors turned on so I can easily spot which he In this model are mark as sharp. But if you need to hide these colored overlays in the edit mode, you can go to the viewport overlays panel up here, and then turn off this sharp option here. Okay. Next, if you want to clear out the sharp property from the ages, you need to select the ages first, and then right click and then choose clear sharp in here. Another method of manually controlling the smooth shading is by applying it at the face level. For example, let's say we want to make the monkey model smooth except the eyebrows.

First select the monkey model and then change the shading mode to smooth. press tab to go to the edit mode and then go to the face mode. Select the faces you want to edit. In my case, I want to alter the polygons at the eyebrows area. Okay, next, right click and then to share flat in here. Now if you go to the object mode, you can see that the eyebrows area is now has a flat shading while the other faces are smooth.

Yes, this method does not offer the precise control like the previous age sharpness method. You can only do either flat or smooth for a face level. But sometimes for simple objects, you can get the job done more quickly using this method