STALKER: Clear Sky Tweak Guide

[Page 7] Advanced Tweaking

There are a range of options which are not accessible via the normal in-game settings, and can only be changed via advanced tweaking. This section looks at these settings and what the major ones do. There are three primary ways to access and alter advanced settings in STALKER: Clear Sky - the in-game console, the user configuration file, and the command line switches. Each of these is covered in a relevant section of its own on the following three pages. We start with the User.ltx file on this page.

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User.ltx Settings

Your personal settings and keyboard configuration for Clear Sky are held in a file called User.ltx, found under the \Documents and Settings\All Users\Shared Documents\STALKER-STCS directory in Windows XP, or the \Users\Public\Documents\STALKER-STCS directory in Windows Vista. This file is automatically loaded up each time Clear Sky starts, and the values in it are implemented by the game's X-Ray engine at that time.

Fortunately you can open it with a text editor like Windows Notepad and alter the values in it, but before making any changes make absolutely sure to create a backup copy of it first. When you open the file you will see a range of settings, most of which are the same as the Console Commands covered on the next page. You can alter any of the values shown and save the file, and the changes will be implemented upon next starting up Clear Sky. Also note that typically if you change a command using the Command Console, the change will be written to User.ltx, so that's typically a quicker way to alter User.ltx - see the next section for more details.

Important Notes:

  • Most of the variables and their usage are the same as in STALKER: Shadow of Chernobyl.
  • Variables which can be completely altered using the in-game settings are not covered below.
  • Only major settings which affect gameplay, image quality and performance will be detailed below. Less significant settings and those which don't appear to have any practical impact are not covered below.
  • Default values aren't shown in most cases because they will differ based on the system and options being used.
  • To see what these settings do on your system, it is best to try them out in the Command Console first to determine its impacts.

  • The list below covers the major settings in alphabetical order and details what they do:

    bind [action, key] - These are your control bindings usually set under the in-game Controls options (See In-Game Settings section). To see the full list of bindable actions, use the bind_list console command first, and bear in mind that any key assigned to an action needs to have the letter k in front of it. For example to assign the space key to the jump action, you need to use bind jump kspace.

    cam_inert [0.0 - 1.0] - Controls the camera inertia, which basically determines how laggy your view will be. It should be left at 0, as values closer to 1.0 make the viewpoint laggier for no real benefit. If you're looking to disable head bobbing/swaying, see the Mods section on page 4.

    g_always_run [on,off] - By default when you move forward, your character is actually running all the time. If this setting is changed to Off, your character will walk forward by default. This is slightly more silent, but obviously slower. Note that neither is to be confused with Sprinting, which is a very fast form of running triggered by pressing another key.

    hud_info [on,off] - This setting allows you to remove all the Heads Up Display (HUD) elements when set to Off, which can be useful for taking screenshots for example. It only appears to disable the NPC Identification function on the HUD in Clear Sky however, you can't turn off the HUD entirely.

    Renderer Settings: An important note regarding the renderer settings below with r1_ r2_ or r3_ prefixes - they only have an impact under certain Render options (See In-Game Settings section). Any setting starting with r1_ only works under the 'Static Lighting' (DX8) renderer; any setting starting with r2_ works in every mode except Static Lighting, though a few may not work properly in the 'Enhanced Full Dynamic Lighting' modes - this is usually noted; any setting starting with r3_ only works in the 'Enhanced Full Dynamic Lighting (DX10)' mode. As with the in-game Advanced graphics options, some of these settings require a full restart of the game to come into effect.

    r1_dlights [on,off] - Controls whether dynamic lighting is enabled using the Static Lighting renderer. Since Static Lighting already removes all dynamic lights, the only effect disabling this option has is to remove your torchlight. This may be useful if you have a very low-end graphics card and find that you're still getting slowdowns.

    r1_dlights_clip [10.000 - 150.000] - Determines the distance before dynamic lights have no impact on the environment. Since the Static Lighting renderer already removes dynamic lights, this option has little to no impact except perhaps on the distance of your torchlight.

    r1_glows_per_frame [2 - 32] - Appears to control the maximum number of light sources, but in practice I've found little performance or visual impact when changing this setting.

    r1_lmodel_lerp [0.000 - 0.333] - This setting controls the Linear Interpolation (Lerp) of the lighting model. As the value is increased, it brightens some textures (e.g. look at your own gun while changing this setting), but the change is otherwise not significant.

    r1_ssa_lod_a [16.000 - 96.000] - Controls the general Level of Detail (LOD) for the game world, with the higher the value, the greater the detail and visibility of objects in the distance, but at a cost of a slight drop in FPS.

    r1_ssa_lod_b [16.000 - 64.000] - This option is similar to the one above, however it appears to control the LOD for certain types of objects within the game world. Once again the higher the value the greater the detail at the cost of some FPS.

    r1_tf_mipbias [-0.500 - 0.500] - Controls the mipmap LOD bias, which in effect determines how clear textures are in the distance. Greater negative values make distant textures far crisper and clearer, but at the cost of reduced FPS and also an increased shimmering effect. Greater positive values make things blurrier and reduce detail, but may improve FPS. This allows you to control texture clarity and crispness in addition to the in-game Anisotropic Filtering slider.

    r2_aa [on,off] - This setting controls whether a blur-shader form of fake Antialiasing is enabled in the game or not. It is not the same as the Antialiasing slider in the game, and is not a real form of Antialiasing. It does not reduce the actual jaggedness of outlines; it masks them by blurring the screen at the cost of some FPS - you can get much the same effect (without the FPS drop) by running an LCD monitor in a non-native resolution for example. Given the in-game Antialiasing slider doesn't work unless you're in DX10 mode, and AA usually cannot be forced by using your graphics card's control panel either, this is an alternative form of allowing you to reduce jaggedness, particularly on foliage in the game. You can control the level of blur used with the r2_aa_ parameters below. Note that using this setting in DX10 mode currently results in major visual glitches.

    r2_aa_kernel [0.300 - 0.700] - This setting controls the overall blur effect used for the fake Antialiasing if the r2_aa option is enabled. The higher the value, the greater the blur effect used. Enabling fake AA and setting this option to 0.3 provides a reasonable fake AA effect without too much blur for example.

    r2_aa_break [0.000000 - 1.000000,0.000000 - 1.000000,0.000000 -1.000000] - This setting appears to control the distance at which the fake AA effect operates. The higher the values used, the further away the effect will be implemented. However because the values are vector-based, setting them all to maximum doesn't necessarily ensure the best result. Experiment to see which values suit your needs (e.g. r2_aa_break 0.000000,1.000000,0.000000 gives sharp close imagery and blurred distance imagery)

    r2_aa_weight [0.000000 - 1.000000,0.000000 - 1.000000,0.000000 - 1.000000] - This setting provides more precise control over the strength of the blurring effect. The higher the values used, the more blurring will be implemented, but again note the values are vector-based.

    r2_allow_r1_lights [on,off] - Enabling this option appears to enhance existing lighting with DX8 lighting. This results in unrealistically bright lighting effect and a drop in FPS, so there should be no reason to implement it.

    r2_dof [0.000000 - 1.000000,0.000000 - 1.000000,0.000000 - 1.000000] - This setting controls the degree of the Depth of Field effect, however it is better to experiment with the individual components of depth of field using the r2_dof_far, r2_dof_near and r2_dof_focus settings below, as they have the same impact. You can then use this setting to commit the changes.

    r2_dof_far [0.000 - 10000.000] - This setting controls the extent to which the Depth of Field is applied to the general scene. Note that it does not just apply to periods when DoF is prominent, such as when reloading your weapon - it applies to the game at all times. Lowering this setting from its default of 600 will increase the general bluriness of distant scenery, creating a form of permanent DoF effect.

    r2_dof_focus [-10000.000 - 10000.000] - This variable is central to the way the rest of the r2_dof_-based settings work, as they take their permissable values from what this is set to. The lower this value is taken from its default of 1.4, the smaller the area of your vision which is 'in focus'. This is most noticeable if you alter the r2_dof_far and r2_dof_near settings to implement permanent depth of field.

    r2_dof_kernel [0.000 - 10.000] - This setting controls the overall level of blur in the depth of field effect. At a value of 0, no depth of field is visible at any time regardless of how you change the r2_dof_-based settings. Higher values make the blurring effect become more prominent when depth of field is used.

    r2_dof_near [-10000.000 - 10000.000] - Similar to the r2_dof_far setting, this setting controls the level of blurring on objects closer to the character - the higher the value of this setting above the default of -1.25, the more blur there is on nearby objects (e.g. your gun) at all times.

    r2_dof_sky [-10000.000 - 10000.000] - Again, much like r2_dof_far and r2_dof_near, this setting permanently applies a depth of field effect to the sky. Higher values above the default of 30 result in greater blurring of the sky.

    r2_gi [on,off] - Disabled by default, this setting appears to control whether Global Illumination is used, a form of lighting which is more realistic, in that lit surfaces then indirectly reflect on and light up other surfaces. There are a range of global illumination parameters starting with r2_gi_ you can use to alter the effect if it is enabled, such as r2_gi_refl which controls the reflectivity of lit surfaces. However enabling global illumination can noticeably reduce FPS. Also note that it doesn't appear to work correctly in the two 'Enhanced Full Dynamic Lighting' modes.

    r2_gloss_factor [0.000 - 10.000] - This setting appears to control the specularity of objects, that is how much they shine and reflect light. The higher the value used, the greater the general gloss on surfaces, at the cost of some FPS. For the most part the default value provides a good level of realistic gloss, though you may wish to fine-tune it.

    r2_ls_bloom_fast [on,off] - This option controls whether an enhanced form of Bloom lighting effect is used in the game. If this option is enabled the enhanced bloom effect will be turned on and will appear quite exaggerated - everything will appear much brighter and hazier. Performance is not greatly affected by this setting. The game already uses HDR lighting by default in everything but the Static Lighting renderer, so this setting merely enhances the existing bloom effect of the HDR, it doesn't replace HDR with Bloom. Note however that you don't need to turn this option on to use the various r2_ls_bloom_ settings below. See below as well as the In-Game Settings section for more details.

    r2_ls_bloom_kernel_b [0.010 - 1.000] - Most noticeable if fast bloom is enabled (though fast bloom is not required for it to work), this option appears to control the overall level of haziness associated with the bloom effect. The higher the value, the more blurring/haziness will be used in the game world's lighting.

    r2_ls_bloom_threshold [0.000 - 1.000] - This setting controls the level of the lighting effect used throughout the game by default, whether or not you have the r2_ls_bloom_fast option enabled. Higher values reduce the brightness of the bloom effect used along with the HDR, such that at 1.000 the game appears similar to the DX8 lighting (but with dynamic lights). You can experiment with altering this value, both with and without fast bloom to achieve a desirable result. For example try Fast Bloom on and a value of 0.350 for this setting to arrive at a slightly more atmospheric look in the game world.

    r2_ls_depth_bias [-0.500 - 0.500] - This setting determines how far the visible light from light sources shines. Lower values increase the depth/boundary of the light cast, any values above 0 essentially clip (remove) the light cast totally. Best left at its default setting.

    r2_ls_depth_scale [0.500 - 1.500] - Similar to the setting above, the practical impact of changing this setting is alter the effect of light cast from light sources, and the resulting impact on shadows. Lower values reduce shadowing - this is best kept at its default.

    r2_mblur [0.000 - 1.000] - This option controls motion blurring in the game. However to have it function, you will first need to apply the -mblur command line switch to the Target box of your STALKER: Clear Sky launch icon properties, and then you can see the effects of changing this variable. A value of 1.0 for example shows noticeable blurring as you turn around, while a value of around 0.1 provides a minor amount of blurring wth no real drop in FPS. Experiment to see what suits you best. Note that motion blur does not appear to work properly in either of the 'Enhanced Full Dynamic Lighting' modes.

    r2_parallax_h [0.000 - 0.500] - This setting appears to control Parallax Mapping, a technique used to further improve the appearance of depth on surfaces. However in my experimentation changing this setting had no visual or performance impact.

    r2_ssa_lod_a [16.000 - 96.000] - Controls the Level of Detail (LOD) for the game world, with the higher the value, the greater the detail and visibility of objects in the distance, but at a cost of a slight drop in FPS.

    r2_ssa_lod_b [32.000 - 64.000] - This option is similar to the one above, however it appears to control the LOD for certain objects. Once again the higher the value the greater the detail at the cost of some FPS.

    r2_ssao_blur [on,off] - This option appears to be related to adjusting the impact of the SSAO setting which can be turned on or off using the in-game settings. However in practice I have not found any noticeable image quality or performance differences when enabling or disabling this option, even after a reboot and in various applicable render modes.

    r2_sun [on,off] - This setting controls whether the Sun is enabled as a light source or not, hence it is the same as the 'Sun Shadows' in-game setting. However if the Sun is enabled, there are also a range of settings starting with r2_sun_ you can use to control various aspects of the Sun's lighting and appearance. Only the more practical of these is covered below.

    r2_sun_depth_far_bias [-0.500 - 0.500]

    r2_sun_depth_far_scale [0.500 - 1.500]

    r2_sun_depth_near_bias [-0.500 - 0.500]

    r2_sun_depth_near_scale [0.500 - 1.500]

    These settings essentially control the level of detail of the shadows cast by the sun, and the boundary of the sun's light and shadow areas. Higher values result in more areas of shadow, negative values result in less shadow. The defaults are generally recommended.

    r2_sun_far [51.000 - 180.000] - This setting seems to control the overall degree to which the sun impacts on the environment; higher values appear to increase shadow strength and the reach of sunlight at a potential drop in FPS.

    r2_sun_lumscale [-1.000 - 3.000] - Determines the level of luminosity (brightness) of the sun's light, with values of zero or below essentially turning off the Sun.

    r2_sun_lumscale_amb [0.000 - 3.000] - This setting controls the ambient (indirect) lighting caused by the Sun. Lower values result in darker overall visuals, higher values brighten up the surrounding area without increasing the direct light from the Sun.

    r2_tf_mipbias [-0.500 - 0.500] - Controls the mipmap LOD bias, which in effect determines how clear textures are in the distance. Greater negative values make distant textures far crisper and clearer, but at the cost of reduced FPS and also an increased shimmering effect. Greater positive values make things blurrier and reduce detail, but may improve FPS. This allows you to control texture clarity and crispness in addition to the in-game Anisotropic Filtering slider. Note that this setting appears to have no effect in DX10 mode.

    r2_tonemap [on,off] - This option controls whether Tone Mapping is used in Clear Sky. Tone Mapping will help improve the appearance of the HDR used in the game, reducing contrasts and highlighting details as necessary to keep the image more realistic. It is recommended that you keep this option enabled, as disabling it gives no real boost to FPS. With tone mapping enabled, you can alter the appearance of the HDR in the game by using the settings further below. The r2_tonemap_middlegray setting in particular has the most noticeable impact on the HDR effect.

    r2_tonemap_lowlum [0.000 - 1.000] - This setting controls the effect of tone mapping on darker areas. The higher this setting, the darker the overall appearance of HDR will be. In general it is best left at its default.

    r2_tonemap_middlegray [0.000 - 2.000] - This setting has the most discernable impact on HDR, and as its value is raised, the HDR effect because more prominent and rich. For example try a value of 1.2 to see the HDR in Clear Sky look more like that used in games like Oblivion.

    r3_dynamic_wet_surfaces_far [30.000 - 100.000] - This setting controls the appearance of wet surfaces further away from your viewpoint. Higher values above the default of 30 make distant wet surfaces more visible and detailed, which may reduce FPS but increase realism.

    r3_dynamic_wet_surfaces_near [10.000 - 70.000] - Similar to the setting above, this setting appears to control the appearance of wet surfaces closer to the viewer. Higher values above the default of 10 progressively remove detail and wetness on nearby surfaces, which can increase FPS at the cost of realism.

    r3_dynamic_wet_surfaces_sm_res [64 - 2048] - This setting appears to control the resolution of the wet surfaces effect, which essentially determines how realistic the effect appears. Higher values above the default of 256 increase the resolution and translucency of detailing in wet surfaces with a slight drop in performance.

    r3_gbuffer_opt [on,off] - This setting appears to control a form of potential rendering optimization for DX10 mode. If set to on it may improve performance, however it is likely it has been disabled by default because it can cause glitches, crashes or due to other bugs. In my testing it didn't appear to cause any problems, but it also didn't seem to improve performance or image quality either. You can experiment to see if it helps you.

    r3_msaa [st_opt_off,2x,4x,8x] - This setting appears to control whether Multisampling Antialiasing is used in DX10 mode, and is the same as the in-game Antialiasing drop-down box when in DX10 mode (introduced as of the 1.5.05 patch). When set to Disabled in the in-game settings, it has a value of st_opt_off. When enabled, you can choose a particular sample rate such as 2x or 4x Antialiasing to apply. Note that any changes to this setting require a restart of the game before you will see proper MSAA being applied to geometry (but not foliage) - and only in DX10 mode.

    The following settings starting with r__ are not specific to any particular render mode, and work under all modes.

    r__supersample [1 - 8] - This setting is the same as the in-game Antialiasing slider, with the value used equal to the sampling rate of AA to be applied - e.g. a value of 8 = 8x AA. However it is important to note that for the most part Antialiasing appears to have no impact in Clear Sky in all but the DX10 render mode, and even then the r3_msaa setting must be On for it to work. In modes other than DX10 you can use the r2_aa setting instead to apply a form of blur Antialiasing.

    r__tf_aniso [1 - 16] - This setting is the same as the in-game Anisotropic Filtering slider, with the value used equal to the sampling rate of AF to be applied - e.g. a value of 16 = 16x AF. However you can also use the r1_tf_mipbias (for Statitc Lighting mode) or r2_tf_mipbias (for the other modes except DX10) setting to give you further control over texture clarity and crispness.

    r__dtex_range [5.000 - 175.000] - This setting controls the distance at which Detail Textures are visible. Detail Textures are the fine level of detailing and grain shown on certain surfaces such as rocks and walls when viewed close up. The higher the value, the further away you will be able to see these detail textures, at a possible cost in performance.

    r__wallmark_ttl [1.000 - 300.000] - This setting controls the length of time in seconds in which decals ('wall marks') are shown on the screen before they fade away (i.e. their 'time to live' or ttl). For example raising the value increases realism at the cost of some performance, particularly during heavy combat scenes, as more decals are left visible for longer.

    rs_stats [on,off] - When set to On, displays a range of game statistics, including the Frames Per Second (FPS) counter in the top left corner of the screen. In most cases though it is easier just to use the free Fraps utility to measure framerate in Clear Sky.

    snd_acceleration [on,off] - This setting controls whether hardware accelerated sound is used in the game when on, or whether software sound is used when off. It should correspond to the option you choose under the Sound Device option in the in-game Sound settings.

    snd_cache_size [4 - 32] - This setting controls the size of the sound cache, a portion of memory used to hold sound effects for quicker loading. A setting of 4 equates to an 8MB cache, while the maximum value of 32 is equal to a cache of 64MB in size. In general you should set this to the highest value possible (32), so that more sounds are cached and there is less in-game loading/stuttering.

    snd_efx [on,off] - This option is meant to enable or disable sound effects, however changing this setting, even after the use of the snd_restart command or a restart, appears to have no impact.

    snd_targets [4 - 32] - This setting appears to determines the number of audio channels used, with the greater the channels specified, the more distinct sounds you can hear, but the lower your overall performance.

    vid_mode [WxH] - Controls the Resolution used for the game, as set under the Resolution option in the in-game settings. Here however you can try setting a custom resolution by entering it in the correct WxH format (e.g. 1280x960 or 640x480) - as long as your monitor supports it. Note that you will have to use the vid_restart console command to implement the change if using this command in the console.

    wpn_aim_toggle [0, 1] - This setting controls whether when you zoom in to aim your weapon (Right Mouse Button by default), you either need to hold down the relevant button to remain zoomed (0), or the weapon remains zoomed until you again press your zoom button (1).

    That covers all the major settings in User.ltx which appear to have some practical worthwhile function. After extensive testing of all the variables, some of the more interesting-sounding commands seem to have no impact whatsoever, so that is why you may see them missing from the list above. If you believe an important working setting has been omitted, or any of the descriptions above are inaccurate, please Email Me with details (please, no guesses), so I can keep this list as up-to-date and accurate as possible.

    The next page continues the Advanced Tweaking by examining the Console Commands.