Simply put, retopology is essentially the process of taking a 3D model with a high poly count and reducing the number of polygons to the smallest number possible to still retain the original shape.
If that sounds confusing, don’t worry, retopology is basically the process of simplifying. I’ve included an article that breaks down 5 tips for helping you improve your retopology, regardless of what software you use.
In addition, there are plenty of awesome tips in further detail over on topologyguides.com so check them out!
First, add a plane into your scene and enable snapping. Next, in edit mode, snap each vertex to the surface of the model that you’re going to retopologize. And then it’s just a matter of extruding that shape over and over until you start to rebuild a lower resolution of your model.
Next, just buckle in for the long haul. It’s not going to be fast. Retopology is going to be a tedious process. Just put on some music and approach it like it’s a puzzle. Just focus on tackling the big shapes and making general pieces come together while keeping your tiles as large as possible without losing detail.
A few weeks back, I tried my hand at creating desert dunes out of a plane. As part of that same project, this week I’m using the cell fracture addon to destroy some statues. I started off with a couple of characters created in MakeHuman. A couple people on blender.chat mentioned that MakeHuman hadn’t been updated in a while, or wasn’t being actively developed. Regardless, the version I used was super easy to generate a couple of characters to use for statue destruction.
Exporting to Blender
Once you’ve got everything how you want it with your character, it’s time to export. Going from MakeHuman to Blender used to be difficult and require a special plugin and weird file extensions. Now, you can just kick out a simple .DAE file and drop it straight into Blender.
Using the Cell Fracture Addon
Once in Blender, I posed the characters exactly how I wanted them. Once I got the pose, I applied the armature. In edit mode, I separated the parts of the mesh I wanted to fracture. I didn’t want the whole thing, just bits like the hand and shoulders. Next, I fractured using a small number of pieces, around 50. I had to mess with the level of subdivisions and number of pieces to avoid weirdness in complex areas like hands and fingers.
Animating vs Simulating
Typically, I’d simulate the pieces after they’re generated. But for this effect, I wanted a surreal, hyper slow-mo look. For this, I just hand animated the pieces I wanted to break away.
It’s kinda like changing the blinker fluid in your car. You can’t. You shouldn’t. I mean… stuff like that doesn’t exist. But, if you’re finding yourself in a situation where you are running shy on your current installed amount of RAM, is there anything you can do without hitting up Newegg for a few more RAM sticks? Luckily, you can! Read on to learn how to add swap memory in Ubuntu 18.04.
Just recently, I tried rendering a complex Blender scene on my computer. Unfortunately it crashed before I ever saw the first tile start to render. Blender was all like, “ERROR: Out of Memory”. I tried rendering again, but this time I opened my system resources window and monitored the RAM usage. I have 16GB of RAM installed, and 2GB of swap. As the scene loaded, the RAM started climbing up to the top of the usage graph, hit the top, then the swap started filling up. They both hit the top, and Blender crashed again.
Fortunately, there’s a somewhat hacky thing called swap memory. So instead of purchasing extra RAM for your machine and going through all the trouble of installing it, you can add “virtual RAM” with just a few lines of code. This swap memory is designed as a sort of fail-safe should your machine demand more RAM memory than is physically installed. My problem was I was exceeding both my physical and my swap memory limitations. By default, Ubuntu was giving me 2GB of swap memory, and I had 16GB of RAM installed, but the Blender scene I was trying to render required more than my physical plus swap total of 18GB.
Step One: Check If You Have Swap Enabled
I’m using Ubuntu 18.04, so I can check my swap status by running this in the terminal:
sudo swapon --show
If there’s no output after running that command, you don’t have any swap memory enabled. If you do have swap enabled, you should get something like this:
NAME TYPE SIZE USED PRIO /dev/sda2 partition 1.9G 0B -2
The swap information in Ubuntu (size and settings and all that) can be found in /swapfile. To enable the swap file, you’d run:
sudo swapon /swapfile
To learn more about the ‘swapon’ and ‘swapoff’ command, you can check out:
man swapon
Step Two: Disable Your Swapfile
Before you edit your swapfile, you need to disable it, otherwise you’ll get an error that’s something like “ERROR: file in use”. To do this, disable your swap file by running:
sudo swapoff /swapfile
Step Three: Edit Your Swapfile
You can edit your current swapfile (or add a new swapfile if you don’t have one) using the fallocate command. You can learn more by running “man fallocate”. To increase your swap memory, run the following command (and change the number of GB to your preference):
sudo fallocate -l 50GB /swapfile
Step Four: Re-Enable Your Swapfile
The -l flag stands for ‘length’ which essentially adjusts how much swap you’ve got. Next, you’ll need to reactivate your swap file by running
sudo swapon /swapfile
Step Five: Confirm Changes Were Applied
That should give your as many GB of swap as you need! You can double check your swap memory by running the Ubuntu System monitor by running:
gnome-system-monitor
and click the Resources tab at the top. You should see your swap memory reflect (not exactly, but pretty close) the amount of swap that you set using the fallocate command.
Swap = 46.6 GB
Now you should be able to render huge scenes in Blender without buying more RAM! Woot!
Just a disclaimer: This is more of a note for myself so I can go back and visit this later. If you spot anything wrong or catch some mistakes, feel free to let me know! Thanks.
