diff --git a/pyradiance/cal.py b/pyradiance/cal.py
index 72de15e..2420b90 100644
--- a/pyradiance/cal.py
+++ b/pyradiance/cal.py
@@ -2,8 +2,8 @@
 Radiance calculation utilites
 """
 
-from pathlib import Path
 import subprocess as sp
+from pathlib import Path
 from typing import Optional
 
 from .anci import BINPATH, handle_called_process_error
@@ -19,6 +19,7 @@ def cnt(
     Args:
         dims: list of dimensions
         shuffled: if True, the output will be shuffled
+
     Returns:
         bytes: output of cnt
 
@@ -52,7 +53,30 @@ def rcalc(
     exact_only=False,
     ignore_newlines=False,
     silent=False,
-):
+) -> bytes:
+    """
+    Run rcalc
+
+    Args:
+        inp: input data
+        sep: separator
+        inform: input format
+        incount: input count
+        outform: output format
+        passive: passive mode
+        pass_negative: pass negative
+        inlimit: input limit
+        outlimit: output limit
+        source: source file
+        expr: expression
+        assign: assign
+        exact_only: exact only
+        ignore_newlines: ignore newlines
+        silent: silent
+
+    Returns:
+        bytes: output of rcalc
+    """
     stdin = None
     cmd = [str(BINPATH / "rcalc")]
     if sep is not None:
@@ -177,6 +201,7 @@ def rlam(
     Args:
         inputs: list of input files or bytes. There can
         only be one bytes input.
+
     Returns:
         bytes: output of rlam
     """
diff --git a/pyradiance/cv.py b/pyradiance/cv.py
index 848969d..7404e6c 100644
--- a/pyradiance/cv.py
+++ b/pyradiance/cv.py
@@ -29,6 +29,7 @@ def obj2rad(
            "o" statements in the input file.  If this option is absent, and there
            are no "o" statements, obj2rad will attempt to name surfaces based
            on their group associations.
+
     Returns:
         The converted RADIANCE scene description in bytes
     """
@@ -69,6 +70,7 @@ def obj2mesh(
         maxres: Maximum octree resolution
         silent: Suppress warnings
         stats: Print statistics
+
     Returns:
         The converted RADIANCE scene description in bytes
     """
@@ -102,6 +104,7 @@ def pkgbsdf(
         xml: Path to XML files
         frozen: produce frozen octree instance for any detail geometry.
         stdout: print the output to stdout, only works for a single XML input.
+
     Returns:
         The output of the command
     """
@@ -152,6 +155,7 @@ def robjutil(
         epsilon: Coalesce vertices that are within the given epsilon
         triangulate: Turns all faces with 4 or more sides into triangles
         transform: Transform the input, using xform CLI syntax.
+
     Returns:
         The output of the command
     """
@@ -189,11 +193,13 @@ def robjutil(
 @handle_called_process_error
 def mgf2rad(*inp, matfile=None, mult=None, dist=None):
     """Convert Materials and Geometry Format file to RADIANCE description.
+
     Args:
         inp: Path to MGF file
         matfile: Path to material file where the translated materials will be written.
         mult: multiplier for all the emission values
         dist: glow distance (in meters) for all emitting surfaces.
+
     Returns:
         The output of the command
     """
@@ -242,6 +248,7 @@ def ies2rad(
         set_default_lamp_color: set default lamp color according to the entry for lamp in the lookup table.
         multiply_factor: multiply all output quantities by this factor. This is the best way to scale
             fixture brightness for different lamps.
+
     Returns:
         The output of the command
     """
@@ -305,6 +312,7 @@ def bsdf2klems(
         backward: generate backward matrixi (default=on).
         expr: expression to evaluate.
         file: file to write the output to
+
     Returns:
         The output of the command
     """
@@ -378,6 +386,7 @@ def bsdf2ttree(
         backward: generate backward matrixi (default=on).
         expr: expression to evaluate.
         file: file to write the output to
+
     Returns:
         Tensor tree BSDF XML in bytes
     """
@@ -449,6 +458,7 @@ def pabopto2bsdf(
            necessary to eliminate noise and edge effects that some measurements exhibit near grazing.
         reverse: reverses the assumed sample orientation front-to-back, and is discussed below under
             the "#intheta" header entry.
+
     Returns:
         SIR data in bytes
     """
diff --git a/pyradiance/gen.py b/pyradiance/gen.py
index ef6a6b0..50d27da 100644
--- a/pyradiance/gen.py
+++ b/pyradiance/gen.py
@@ -92,6 +92,7 @@ def genbsdf(
         geom_unit: Set to a unit to use for geometry BSDF.
         dim: Set to a list of 6 numbers to use for geometry BSDF.
         kwargs: Additional parameters to pass to genBSDF.
+
     Returns:
         str: Output of genBSDF.
     """
@@ -172,6 +173,7 @@ def gendaylit(
         dirnormp: direct normal illuminance
         diffhorp: diffuse horizontal illuminance
         solar: if True, include solar position
+
     Returns:
         str: output of gendaylit
     """
@@ -405,6 +407,7 @@ def gensky(
         solar_radiance: solar radiance in watts/steradian/meter^2
         horizontal_direct_irradiance: horizontal direct irradiance in watts/meter^2
         turbidity: turbidity factor
+
     Returns:
         str: output of gensky
     """
@@ -481,6 +484,7 @@ def genssky(
         solar_radiance: solar radiance in watts/steradian/meter^2
         horizontal_direct_irradiance: horizontal direct irradiance in watts/meter^2
         turbidity: turbidity factor
+
     Returns:
         str: output of gensky
     """
@@ -519,6 +523,7 @@ def mkillum(
         octree: octree file
         nproc: number of processes
         params: additional parameters
+
     Returns:
         Output of mkillum in bytes
     """
diff --git a/pyradiance/ot.py b/pyradiance/ot.py
index d1ac50f..5cf246c 100644
--- a/pyradiance/ot.py
+++ b/pyradiance/ot.py
@@ -14,9 +14,11 @@ def getbbox(
     header: bool = False,
 ) -> List[float]:
     """Get axis-aligned bounding box of a Radiance scene.
+
     Args:
         path: path to Radiance scene
         header: include header
+
     Returns:
         list: bounding box
     """
@@ -31,12 +33,14 @@ def getbbox(
 @handle_called_process_error
 def oconv(*paths, warning=True, stdin=None, frozen: bool = False, octree=None) -> bytes:
     """Run Radiance oconv tool to build an octree.
+
     Args:
         paths: list of Radiance files
         warning: if False, warnings will be suppressed
         stdin: if not None, stdin will be used
         frozen: if True, the octree will be frozen
         octree: if provided, the resulting octree incorporate existing one
+
     Returns:
         bytes: output of oconv
     """
diff --git a/pyradiance/px.py b/pyradiance/px.py
index 6b7dc79..19f06e3 100644
--- a/pyradiance/px.py
+++ b/pyradiance/px.py
@@ -109,6 +109,7 @@ def pcompos(
         label_height: label height
         ncols: number of columns
         anchor_point: anchor point
+
     Returns:
         bytes: output of pcompos
     """
@@ -204,6 +205,7 @@ def pcond(
         primaries: Color primaries for color loss.
         macbeth: Macbeth chart file for color loss.
         mapfile: Color map file for color loss.
+
     Returns:
         bytes: output of pcond
     """
@@ -286,6 +288,7 @@ def pfilt(
         star_points: Number of points on a start pattern.
         star_spread: star pattern spread
         average_hot: average hot spots
+
     Returns:
         bytes: output of pfilt
     """
@@ -425,6 +428,7 @@ def pvalue(
         interleaving: if True, interleaving will be used
         brightness: if True, only brightness will be returned
         outprimary: output color primaries
+
     Returns:
         bytes: output of pvalue
     """
@@ -489,6 +493,7 @@ def pvaluer(
         header: Set to True if the picture file has a header. Default is False.
         primaries: List of primaries for XYZ calculation. Default is None.
         pxyz: Set to True to calculate XYZ values. Default is False.
+
     Returns:
         Bytes of the pvalue output
     """
@@ -551,6 +556,7 @@ def ra_tiff(
             to a RADIANCE picture. Default is False.
         xyze: Set to True to use XYZE output when invoking a reverse
             conversion. Default is False.
+
     Returns:
         bytes: output of ra_tiff
     """
@@ -619,6 +625,7 @@ def ra_ppm(
         exposure: Exposure value for the output image. Default is 0.
         ascii: Set to True to use ASCII Pixmap output. Default is False.
         outscale: Output scale value. Default is 255.
+
     Returns:
         bytes: output of ra_ppm
     """
diff --git a/pyradiance/rt.py b/pyradiance/rt.py
index 20370b8..a2b4161 100644
--- a/pyradiance/rt.py
+++ b/pyradiance/rt.py
@@ -235,6 +235,7 @@ def rcontrib(
     params: Optional[Sequence[str]] = None,
 ) -> bytes:
     """Run rcontrib command.
+
     Args:
         inp: A bytes object.
         octree: A path to octree file.
@@ -244,6 +245,7 @@ def rcontrib(
         inform: Input format.
         outform: Output format.
         params: A list of additional parameters.
+
     Returns:
         A bytes object.
     """
@@ -275,6 +277,7 @@ def rpict(
     params: Optional[Sequence[str]] = None,
 ) -> bytes:
     """Get rpict command.
+
     Args:
         view: A list of view parameters in strings.
         octree: A path to octree file.
@@ -283,6 +286,7 @@ def rpict(
         report: Report.
         report_file: Report file.
         params: A list of additional parameters.
+
     Returns:
         A bytes object.
     """
@@ -325,6 +329,7 @@ def rtrace(
     version: bool = False,
 ) -> bytes:
     """Run rtrace.
+
     Args:
         rays: A string of bytes representing the input rays.
         octree: Path to octree file.
@@ -348,6 +353,7 @@ def rtrace(
         yres: Y resolution of the output image.
         nproc: Number of processors to use.
         options: A SamplingParameters object.
+
     Returns:
         A string of bytes representing the output of rtrace.
     """
diff --git a/pyradiance/util.py b/pyradiance/util.py
index c3619f8..4179c22 100644
--- a/pyradiance/util.py
+++ b/pyradiance/util.py
@@ -1105,6 +1105,7 @@ def xform(
         mirrorx: Mirror the scene about the yz plane.
         mirrory: Mirror the scene about the xz plane.
         mirrorz: Mirror the scene about the xy plane.
+
     Returns:
         The transformed scene description in bytes
 
@@ -1153,6 +1154,7 @@ def load_material_smd(
         roughness: Roughtness of material
         spectral: Output spectral primitives
         metal: Material is metal
+
     Returns:
         A list of primitives
     """
@@ -1204,6 +1206,7 @@ def load_material_smd(
 
 def parse_primitive(pstr: str) -> List[Primitive]:
     """Parse Radiance primitives inside a file path into a list of dictionary.
+
     Args:
         pstr: A string of Radiance primitives.