A complete beginner's guide to making cute Clem renders (Clemders?) in SFM
I suggest reading this in its entirety to get an idea what you're getting yourself into.

The first thing you need to do is pick a theme. If I can't think of anything, I usually ask /ttgg/ for requests. Greentext stories are also a good source of inspiration.

Next, plan out the scene in your head. Figure out what props you need ahead of time, and see if you can get them from the Workshop. Since this is your first time, you're gonna have to download a Clem model. As others have pointed out, Croix's model is the only one out there with face and eye posing, so you're probably gonna have to use it. Just bite the bullet and go download it. However, if you're working on a scene where Clem's face isn't visible (i.e. the Just Dance request I filled where she's facing the TV), it's better to a SFW model that has no faceposing. This is because Clem's body can clip through her clothes with Croix's model. Garry's Mod is a good source of miscellaneous props since its workshop is a lot more populated than SFM's, but you have to extract the addons in order to use them in SFM. I'll put instructions for that somewhere near the bottom of this file.

After opening SFM, create a new session. Framerate is irrelevant for single renders. You then have to choose a map by right clicking the viewport and clicking Load Map. I mostly use CS:GO maps since they are very detailed and varied, but you need to download the maps here http://thekinsie.com/sfm/maps.html . TF2 maps are even more varied and plentiful, but I find their style a little too exaggerated for my tastes. At any rate, you'll probably need to improvise on this since there is no map that will fit your exact requirements.

In order to place and move around objects and the camera in the scene, you'll need to be in either the motion editor (F3) or the graph editor (F4). The motion editor should work fine for anything that isn't an animation. Once you've enabled the motion editor, take some time to familiarize yourself with the camera controls. Click and drag in the viewport to look around, use the standard WASD to move, and scroll to adjust FOV. Right click to bring up a context menu with a couple of useful options. Don't concern yourself with render settings yet, but disabling lighting and progressive refinement may help responsiveness in the preview if you're having performance problems. Some maps may have props already placed on them that can be seen by enabling "World Static Props" and "Other Entities" under "Draw Game Entities".

Add a prop by clicking the plus button in the Animation Set Editor (I will call it the ASE from now on) on the left side of the screen and selecting "Create Animation Set For New Model". Make use of the model browser's filter function. Sometimes models don't show up right in the preview, you might have to spawn them in to see them correctly. Spawning your first prop will also create a scene camera which is the main camera you will use to render. You can switch between this camera and the work camera by clicking the button to the right of the movie reel and play control buttons. As its name implies, use the work camera to move around the scene and adjust poses, props, etc. and switch to the main camera periodically to preview your final scene. You'll probably want to keep the scene camera's FOV relatively low to reduce distortion. As a note, props spawn in front of the scene camera in case you can't find them.

Move the prop roughly into the position you want it in by clicking its entry in the ASE and switching to the Move tool (4-arrow icon bottom left of the preview). The cyan square moves it relative to the screen, while the arrows move in "cardinal" x/y/z directions and the circles move on a plane. Pressing shift while moving with the cyan square will snap to the nearest surface behind the square, so use this to keep the prop on the ground. Be sure to release shift before releasing the mouse button, otherwise you might screw up your time selection in the motion editor. The rotation tool is pretty self-explanatory. You can also scale props, see the bottom of this file if you need to do that later.

Sooner or later, you're gonna have to spawn Clem. If using Croix's model, avert your eyes (camera), as she will be in her birthday suit. Correct this by right clicking her in the ASE, going to "Set Body Groups" and giving her a shirt/jacket and trousers. This is also where you can add or remove her hat, shoes, et cetera. I often have to remove her sleeves to reduce the clipping problems I mentioned earlier.

To make posing easier, give Clem an IK (Inverse Kinematics) rig. Right click her in the ASE, and select "rig_biped_simple" under "Rig". Be warned that having the rig loaded also prevents access to a couple of face poses, so you might want to detach the rig through the same menu once you get the overall pose down. IK rigs are useful because they essentially let you set "targets" for where you want her hands/feet to be instead of having to move every bone individually.

Once you have Clem roughly where you want her by moving her like you did the prop before, expand her entry in the ASE. What you mostly want to work with here are rig_foot_R/L and rig_hand_R/L, so expand the relevant nodes in the tree. Selecting any of these elements will allow you to pose them similarly to how you move props around. Try selecting one of her hands and moving it around to see how the IK rig works. Knee and elbow nodes don't explicity pose her knees or elbows, but they provide a "hint" as to what direction they should stick out, so you might want to move these around too. Besides her limbs, you can move her torso around first by moving the pelvis bone, and then rotating the spine, neck, and head bones. You generally can't translate (use the move tool) these bones without serious deformation of the model. The clavicle bones are the same deal. Basically, if moving a bone causes the model to deform unnaturally, you should be rotating it instead. Finger posing is incredibly annoying and I suggest finding a way to avoid it, but if you must, use your own hand as a reference. Finger bones should only ever be rotated.

Face posing is my favorite part. You can control what Clem looks at via the "viewTarget" node. As mentioned before, some of the face poses are "locked out" by the IK rig (notably, the mouth opening slider and some eyelid ones), so save this part for last after you've detached the IK rig. Use a reference for this part, since making a convincing expression is one of the most important things you can do in a render. To do face posing, select "Face" and "Unknown" in the ASE. The sliders will appear between the tree view and the preview window. Just mess with these for a bit. Some of the sliders are linked and control both the left and right sides (i.e. left/right eyebrows), use the L/R slider above the list to weight how much you affect each side. Be sure to experiment with everything. Making her look happy takes more than just raising the "smile" slider, you'll probably also want to raise her cheeks, eyelids, eyebrows, etc.

You may need additional lights in your scene; add one through the plus button in the ASE. Lights are a bit tricky because they're directional, so it may help to right click the light in the ASE and click "Enable Light Frustum" so you can see what direction the light is pointing in the preview. These frustums don't show up in the final render so feel free to leave them on. Play with the light's sliders to adjust its properties until it looks right. Don't be afraid to use multiple lights, look up three point lighting as a basic starting point for decent lighting design.

Finally, when it comes time to render, you need to do a few things. In the ASE, create an animation set "for existing element(s)", choosing camera1. By selecting camera1 in the ASE, you can adjust bloom and ambient occlusion properties using the sliders. You'll notice that the ambient occlusion shadows are quite grainy in the preview, to fix that for the final render (it'll still look grainy in the preview), right click the preview window and go to Render Settings. Raise the number of samples for depth of field and motion blur to something like 128 and 64, respectively. When you're ready to render, go to File, Export... and click Poster. You might as well go all out and render at a really high resolution, you can always resize it later. I usually go for 3840x2160. You can tell it to export a JPG, but I usually open up the TGA in Paint.net and save it myself so I have more control over quality and filesize. This also allows me to resize if necessary, and touch up any parts of the image that need it such as covering up minor clipping errors.

Take a look at the final product, making adjustments if necessary. Once you're happy with it, post it so we can all see your hard work! It can be a real hassle to make some of these images, but it's all worth it in the end once you know you've made a bunch of other people happy. If you get good enough at it, you can try moving on to animations! But that's best left for another guide.



Here are a couple of other miscellaneous things that didn't really fit into the guide I wrote above:

To scale a prop, right click its "rootTransform" bone and select "Add Scale Control To Transforms". This will add a slider allowing you to adjust the scale. 0.1 is regular size, with 0.01 being 1/10th size and 1.0 being 10x size. You can also scale individual bones by right clicking them instead of rootTransform.
Scaling props can come in quite handy, especially since Clem is smaller than an adult. Don't be afraid to add some subtle scaling to her or the props around her to make the scene look more convincing.

If you really can't find a prop you need, improvise. I've used things like scaled-down waterfall props to fake water running from a faucet or a bottle cap as a refrigerator magnet. If you don't mind getting your hands dirty, reskin props into what you need by editing their material files. The console command "mat_reloadallmaterials" is useful if you're trying this.

To use Garry's Mod content, you first need to boot up Garry's Mod so it downloads the files. Then, locate the .gma file in your garrysmod/addons folder. You need to use a program called gmad to extract this, which is included with GMod. The easiest way I've found to do this is to open a command prompt in the addons folder (SHIFT+Right click an empty spot in the folder and click "Open command window here", and then use the command:
..\..\bin\gmad.exe extract -file addonfilenamehere.gma -out extract
This will extract the contents of the addon into a folder called "extract" in the addon folder. You can then take the contents of this and put it in your usermod folder.

You can switch between local and global axes while moving or rotating something by right clicking the rotation/translation widget thing.