Depending on the situation, which is sadly not possible to see here (it could help if you attach a picture of your view), i would recommend to press Numpad Decimal or go in the "View" Menu and click on "Frame Selected".
If you zoom in enough on a small detail, the amount of movement with the mouse seems to get drastically reduced.
Once you use "Frame ...
You can change the Viewport Shading in the top right corner of the 3D editor. Open up the drop-down menu by pressing the upside-down ^, then select MatCap. Then, press the ball to change which MatCap you want to use.
I believe this is the one you're seeing in the video.
Note that these settings will only be visible if you're in the Solid Viewport Shading ...
You can save the HDRI in Blender by going to the file tab in the upper left corner, and selecting external files. This will give you an option to pack all external files into the .blend so that you can save it in the file.
It is possible!
A few steps needed for it though.
You have to use a camera for this to work, the camera can be set up so the boundaries are at the edges of the screen, activating "lock camera to view" (function is in my favorites menu) makes it then possible to look around and rotate the view while staying in the camera.
After setting up the camera view, ...
This, if it was an imported model, could have been sculpted with dyntopia sculpting. It may have also been modeled in edit mode, instead of sculpting. In this case, the best way to achieve a nice-looking result would be to subdivide, or to save memory, subdivide those faces.
I believe that the issue is arising from either one of the situations below.
1) When you switch to Sculpt mode, the sculpting tools will only act on the previously selected object. Switch back to the Layout mode and make sure that you've got the sculpting object selected.
2) Your object may not have enough geometry to be sculpted on since the sculpting ...
I already found he answer myself: It turned out that the version of the Heavypoly UI Config that I used had the dyntopo parameter integrated by default into the script that facilitates the switch into sculpt mode from a pie menu ;)
Shading artifacts is a common problem using the Boolean workflow. Using the bevel modifier with a very small width can help mitigate the problem. After that, consider marking any edges surrounding flat surfaces as sharp.
Finally, tab into Edit Mode and look for any double vertices or incorrectly shaded n-gons and fix these issues manually. Double vertices ...
A couple of screenshots would go a long way in helping you explain your situation.
I'm going to guess that you have a lot of unnecessary polygons on your models. If you want your game to run smoothly or not require excessive computing power, you're going to want to optimize your models by reducing the vertex/face count.
If you insert a vertex into a side ...
I had this problem and in my case it was because my mesh was originally huge and I scaled it down by 1000 times. Then when trying to move vertices, they were moving very slowly. Once I applied the scaling, then the movement was normal again.