diff --git a/HISTORY.md b/HISTORY.md
index 4b4ae32..c34a831 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,5 +1,25 @@
 # camelSCAD history
 
+## [Version 1.6.0](https://github.com/jsconan/camelSCAD/releases/tag/v1.6.0)
+
+Add core functions:
+
+-   `interpolationThreshold()`: Computes the threshold for a particular interpolation step considering the expected number of steps, and with respect to start and end thresholds.
+
+Add operators:
+
+-   `presentAnimate()`: Presents the child modules only between the start and end thresholds, with respect to the `$t` variable.
+
+Update script utils:
+
+-   Add color for the warning messages.
+-   Add the function `buildpath` to build a destination path from a list of parts.
+-   Add the function `scadversion` to get the version of the installed OpenSCAD.
+-   Add the function `sclic3rversion` to get the version of the installed Slic3r.
+-   Add the function `scadpreview` to render a capture of a SCAD model.
+-   Add the function `scadecho` to capture the echos printed by a model.
+-   Accept other parameters than variable definitions when calling OpenSCAD.
+
 ## [Version 1.5.0](https://github.com/jsconan/camelSCAD/releases/tag/v1.5.0)
 
 Add operators to ease scenes animation:
diff --git a/core/maths.scad b/core/maths.scad
index df322e5..975bf27 100644
--- a/core/maths.scad
+++ b/core/maths.scad
@@ -528,3 +528,24 @@ function interpolateStep(step, low, high, start, end, domain, values, range) =
        :simpleInterpolationRange(low=low, high=high, start=start, end=end, domain=domain)
     )
 ;
+
+/**
+ * Computes the threshold for a particular interpolation step considering the expected number of steps,
+ * and with respect to start and end thresholds.
+ * @param Number step - The current step.
+ * @param Number steps - The total number of expected steps.
+ * @param Number [start] - The start threshold under what the low value will persist and above what it will be interpolated.
+ * @param Number [end] - The end threshold above what the high value will persist and under what it will be interpolated.
+ * @param Number [domain] - The percentage domain applied to compute the percentage ratio for the thresholds (default: 100).
+ * @returns Number
+ */
+function interpolationThreshold(step, steps, start, end, domain) =
+    let(
+        step = float(step),
+        steps = divisor(steps),
+        start = abs(percentage(numberOr(start, 0), domain=domain)),
+        end = abs(percentage(numberOr(end, 1), domain=domain)),
+        range = max(start, end) - min(start, end)
+    )
+    start + step * range / steps
+;
diff --git a/core/version.scad b/core/version.scad
index 4838473..b18fb89 100644
--- a/core/version.scad
+++ b/core/version.scad
@@ -36,7 +36,7 @@
  * The version of the library.
  * @type Vector
  */
-CAMEL_SCAD_VERSION = [1, 5, 0];
+CAMEL_SCAD_VERSION = [1, 6, 0];
 
 /**
  * The minimal version of OpenSCAD required by the library.
diff --git a/operator/animate/mirror.scad b/operator/animate/mirror.scad
index fba6f52..d1c87b3 100644
--- a/operator/animate/mirror.scad
+++ b/operator/animate/mirror.scad
@@ -42,7 +42,6 @@
  * @param Number [domain] - The percentage domain used to compute the thresholds (default: 100).
  * @param Vector [values] - A list of axis composing the range to interpolate.
  * @param Vector [range] - A pre-built interpolation range. If missing, it will be built from the parameters `from`, `to`, `start`, `end`, `domain`.
- * @returns Number
  */
 module mirrorAnimate(from, to, start, end, domain, values, range) {
     mirror(interpolateStep3D(step=$t, low=from, high=to, start=start, end=end, domain=domain, values=values, range=range)) {
diff --git a/operator/animate/present.scad b/operator/animate/present.scad
new file mode 100644
index 0000000..88164f0
--- /dev/null
+++ b/operator/animate/present.scad
@@ -0,0 +1,48 @@
+/**
+ * @license
+ * MIT License
+ *
+ * Copyright (c) 2022 Jean-Sebastien CONAN
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/**
+ * Part of the camelSCAD library.
+ *
+ * Operators that animate child modules with respect to particular rules.
+ *
+ * @package operator/animate
+ * @author jsconan
+ */
+
+/**
+ * Presents the child modules only between the start and end thresholds, with respect to the `$t` variable.
+ *
+ * @param Number [start] - The start threshold under what the child modules will be hidden and above what they will be presented.
+ * @param Number [end] - The end threshold above what the child modules will be hidden and under what they will be presented.
+ * @param Number [domain] - The percentage domain used to compute the thresholds (default: 100).
+ */
+module presentAnimate(start, end, domain) {
+    start = abs(percentage(numberOr(start, 0), domain=domain));
+    end = abs(percentage(numberOr(end, 1), domain=domain));
+    if( $t >= min(start, end) && $t <= max(start, end) ) {
+        children();
+    }
+}
diff --git a/operator/animate/resize.scad b/operator/animate/resize.scad
index 0c23480..936ebd0 100644
--- a/operator/animate/resize.scad
+++ b/operator/animate/resize.scad
@@ -43,7 +43,6 @@
  * @param Vector [values] - A list of sizes composing the range to interpolate.
  * @param Vector [range] - A pre-built interpolation range. If missing, it will be built from the parameters `from`, `to`, `start`, `end`, `domain`.
  * @param Boolean [auto] - When set to `true`, it auto-scales any 0-dimensions to match. It can also be used to auto-scale a single dimension and leave the other as-is.
- * @returns Number
  */
 module resizeAnimate(from, to, start, end, domain, auto, values, range) {
     resize(interpolateStep3D(step=$t, low=from, high=to, start=start, end=end, domain=domain, values=values, range=range), auto=auto) {
diff --git a/operator/animate/rotate.scad b/operator/animate/rotate.scad
index 96cbe86..660d759 100644
--- a/operator/animate/rotate.scad
+++ b/operator/animate/rotate.scad
@@ -42,7 +42,6 @@
  * @param Number [domain] - The percentage domain used to compute the thresholds (default: 100).
  * @param Vector [values] - A list of angles composing the range to interpolate.
  * @param Vector [range] - A pre-built interpolation range. If missing, it will be built from the parameters `from`, `to`, `start`, `end`, `domain`.
- * @returns Number
  */
 module rotateAnimate(from, to, start, end, domain, values, range) {
     rotate(interpolateStep3D(step=$t, low=from, high=to, start=start, end=end, domain=domain, values=values, range=range)) {
diff --git a/operator/animate/scale.scad b/operator/animate/scale.scad
index 73e7c51..ec84c47 100644
--- a/operator/animate/scale.scad
+++ b/operator/animate/scale.scad
@@ -42,7 +42,6 @@
  * @param Number [domain] - The percentage domain used to compute the thresholds (default: 100).
  * @param Vector [values] - A list of scale ratios composing the range to interpolate.
  * @param Vector [range] - A pre-built interpolation range. If missing, it will be built from the parameters `from`, `to`, `start`, `end`, `domain`.
- * @returns Number
  */
 module scaleAnimate(from, to, start, end, domain, values, range) {
     scale(interpolateStep3D(step=$t, low=from, high=to, start=start, end=end, domain=domain, values=values, range=range)) {
diff --git a/operator/animate/translate.scad b/operator/animate/translate.scad
index e5bacab..31e6705 100644
--- a/operator/animate/translate.scad
+++ b/operator/animate/translate.scad
@@ -42,7 +42,6 @@
  * @param Number [domain] - The percentage domain used to compute the thresholds (default: 100).
  * @param Vector [values] - A list of coordinates composing the range to interpolate.
  * @param Vector [range] - A pre-built interpolation range. If missing, it will be built from the parameters `from`, `to`, `start`, `end`, `domain`.
- * @returns Number
  */
 module translateAnimate(from, to, start, end, domain, values, range) {
     translate(interpolateStep3D(step=$t, low=from, high=to, start=start, end=end, domain=domain, values=values, range=range)) {
diff --git a/operators.scad b/operators.scad
index bd7da2e..ac992ff 100644
--- a/operators.scad
+++ b/operators.scad
@@ -36,6 +36,7 @@ include <core.scad>
 
 /* OPERATORS */
 include <operator/animate/mirror.scad>
+include <operator/animate/present.scad>
 include <operator/animate/resize.scad>
 include <operator/animate/rotate.scad>
 include <operator/animate/scale.scad>
diff --git a/scripts/render.sh b/scripts/render.sh
index 02373e2..21808e2 100755
--- a/scripts/render.sh
+++ b/scripts/render.sh
@@ -112,7 +112,7 @@ if [ ! -d "${srcpath}" ]; then
     printerror "The input path ${srcpath} does not exist!"
 fi
 if [ ! -d "${dstpath}" ]; then
-    printmessage ${C_ERR}"Warning! The output path ${dstpath} does not exist!"
+    printmessage ${C_WRN}"Warning! The output path ${dstpath} does not exist!"
 fi
 
 # check OpenSCAD
diff --git a/scripts/slice.sh b/scripts/slice.sh
index 399c697..1b2eda8 100755
--- a/scripts/slice.sh
+++ b/scripts/slice.sh
@@ -126,7 +126,7 @@ if [ ! -d "${srcpath}" ]; then
     printerror "The input path ${srcpath} does not exist!"
 fi
 if [ ! -d "${dstpath}" ]; then
-    printmessage ${C_ERR}"Warning! The output path ${dstpath} does not exist!"
+    printmessage ${C_WRN}"Warning! The output path ${dstpath} does not exist!"
 fi
 
 # check Slic3r
@@ -137,7 +137,7 @@ slic3rformat "${format}"
 
 # defines the config path
 if [ "${configpath}" != "" ] && [ ! -f "${configpath}" ]; then
-    printmessage "${C_ERR}Warning! The config for Slic3r does not exist."
+    printmessage "${C_WRN}Warning! The config for Slic3r does not exist."
 fi
 slic3rconfig "${configpath}"
 
diff --git a/scripts/test.sh b/scripts/test.sh
index dc4c0db..feab7db 100755
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -101,7 +101,7 @@ if [ ! -d "${srcpath}" ]; then
     printerror "The input path ${srcpath} does not exist!"
 fi
 if [ ! -d "${dstpath}" ]; then
-    printmessage ${C_ERR}"Warning! The output path ${dstpath} does not exist!"
+    printmessage ${C_WRN}"Warning! The output path ${dstpath} does not exist!"
 fi
 
 # check OpenSCAD
diff --git a/scripts/utils/display.sh b/scripts/utils/display.sh
index ca72b0f..a217453 100644
--- a/scripts/utils/display.sh
+++ b/scripts/utils/display.sh
@@ -34,6 +34,7 @@
 
 # List of color codes
 export C_ERR="\033[31m"
+export C_WRN="\033[35m"
 export C_SEL="\033[32m"
 export C_SPE="\033[33m"
 export C_CTX="\033[36m"
diff --git a/scripts/utils/files.sh b/scripts/utils/files.sh
index b246d4e..824ab94 100644
--- a/scripts/utils/files.sh
+++ b/scripts/utils/files.sh
@@ -2,7 +2,7 @@
 #
 # GPLv3 License
 #
-# Copyright (c) 2019 Jean-Sebastien CONAN
+# Copyright (c) 2019-2022 Jean-Sebastien CONAN
 #
 # This file is part of jsconan/things.
 #
@@ -128,3 +128,33 @@ recursepath() {
         fi
     done
 }
+
+# Builds a file path.
+#
+# @example
+# buildpath "bar.scad" "foo/bar"                   # will build the path foo/bar/bar.scad
+# buildpath "bar.scad" "foo/bar" "" "foo"          # will build the path foo/bar/foo-bar.scad
+# buildpath "bar.scad" "foo/bar" "" "" "baz"       # will build the path foo/bar/bar-baz.scad
+# buildpath "bar.scad" "foo/bar" "" "foo" "baz"    # will build the path foo/bar/foo-bar-baz.scad
+# buildpath "bar.scad" "foo/bar" "stl"             # will build the path foo/bar/bar.stl
+# buildpath "bar.scad" "foo/bar" "stl" "foo"       # will build the path foo/bar/foo-bar.stl
+# buildpath "bar.scad" "foo/bar" "stl" "" "baz"    # will build the path foo/bar/bar-baz.stl
+# buildpath "bar.scad" "foo/bar" "stl" "foo" "baz" # will build the path foo/bar/foo-bar-baz.stl
+#
+# @param filepath - The path to the original file.
+# @param destpath - The path to the file.
+# @param extension - A file extension to set to the file name.
+# @param prefix - A prefix to add to the file name.
+# @param suffix - A suffix to add to the file name.
+buildpath() {
+    local filepath="$1";
+    local destpath="$2";
+    local extension=$(prefixif "." "$3");
+    local prefix=$(suffixif "$4" "-");
+    local suffix=$(prefixif "-" "$5");
+    local name=$(basename "${filepath%.*}")
+    if [ "${extension}" == "" ]; then
+        extension=$(prefixif "." "${filepath##*.}");
+    fi
+    echo "${destpath}/${prefix}${name}${suffix}${extension}"
+}
diff --git a/scripts/utils/scad.sh b/scripts/utils/scad.sh
index f23cd3a..e705554 100644
--- a/scripts/utils/scad.sh
+++ b/scripts/utils/scad.sh
@@ -41,6 +41,9 @@ export scadver="2019.05"
 # Defines the file extension for OpenSCAD files
 export scadext="scad"
 
+# Defines the file extension for echo prints
+export echoext="echo"
+
 # Defines the file format for the rendering output
 export scadout="stl"
 
@@ -91,6 +94,28 @@ scadmoduleuri() {
     fi
 }
 
+# Gets the version of the installed OpenSCAD.
+# Exits with error code E_OPENSCAD if not installed.
+#
+# @example
+# scadversion       # will display "xxxx.xx"
+#
+# scadversion "foo" # will display "xxxx.xx", or return E_OPENSCAD if not installed
+#
+# @param [openscad] - The path to the OpenSCAD command (default "openscad").
+scadversion() {
+    local version
+    local cmd="${scadcmd}"
+    if [ "$1" != "" ]; then
+        cmd="$1"
+    fi
+    version=$(${cmd} -v 2>&1)
+    if [ "$?" != "0" ]; then
+        return ${E_OPENSCAD}
+    fi
+    echo "${version//[^0-9.]/}"
+}
+
 # Checks if OpenSCAD is installed.
 # Exits with error code E_OPENSCAD if not installed.
 #
@@ -105,19 +130,19 @@ scadmoduleuri() {
 #
 # @param [openscad] - The path to the OpenSCAD command (default "openscad").
 scadcheck() {
-    local info=
+    local info
+    local version
     if [ "$1" != "" ]; then
         scadcmd="$1"
         info=" [from ${C_SEL}${scadcmd}${C_RST}]"
     fi
     printmessage "Detecting ${C_SPE}OpenSCAD${C_RST}${info}..."
-    local scad=$(${scadcmd} -v 2>&1)
+    version=$(scadversion)
     if [ "$?" != "0" ]; then
         printerror "It seems OpenSCAD has not been installed on your system.\nOr perhaps is it just not reachable...\nHave you placed it in your environment PATH variable?" ${E_OPENSCAD}
     else
         printmessage "${C_SPE}OpenSCAD${C_RST} has been detected."
     fi
-    local version="${scad//[^0-9.]/}"
     if [[ "${version}" < "${scadver}" ]]; then
         printerror "The installed version of OpenSCAD does not meet the requirement.\n\tInstalled: ${version}\n\tRequired: ${scadver}" ${E_OPENSCAD}
     fi
@@ -141,11 +166,13 @@ scadcall() {
     local params=()
     for var in "$@"; do
         if [ "${var}" != "" ]; then
-            params+=("-D")
+            if [[ "${var}" == *=* ]]; then
+                params+=("-D")
+            fi
             params+=("${var}")
         fi
     done
-    ${scadcmd} --render -o "${outputpath}" "${sourcepath}" "${params[@]}"
+    ${scadcmd} -o "${outputpath}" "${sourcepath}" "${params[@]}"
 }
 
 # Set the format of the ouput files.
@@ -188,20 +215,60 @@ scadprocesses() {
 # scadrender "bar.scad" "foo/bar" "foo" "baz" # will render a STL file at foo/bar/foo-bar-baz.stl
 #
 # @param filepath - The path of the SCAD file to render.
-# @param destpath - The path to the output file.
+# @param destpath - The path to the output folder.
 # @param prefix - A prefix to add to the output file.
 # @param suffix - A suffix to add to the output file.
 # @param ... - A list of pre-defined variables.
 scadrender() {
-    local filepath="$1"; shift
-    local destpath="$1"; shift
-    local prefix=$(suffixif "$1" "-"); shift
-    local suffix=$(prefixif "-" "$1"); shift
+    local filepath="$1";
+    local filename=$(basename "${filepath}")
+    local outputpath=$(buildpath "$1" "$2" "${scadout}" "$3" "$4")
+    shift $(($# > 4 ? 4 : $#))
+    printmessage "${C_RST}Rendering of ${C_SEL}${filename}${C_RST} to ${C_SEL}${outputpath}"
+    scadcall "${filepath}" "${outputpath}" --render "renderMode=\"prod\"" "$@"
+}
+
+# Previews a module.
+#
+# @example
+# scadpreview "bar.scad" "foo/bar" "png"             # will preview a STL file at foo/bar/bar.png
+# scadpreview "bar.scad" "foo/bar" "png" "foo"       # will preview a STL file at foo/bar/foo-bar.png
+# scadpreview "bar.scad" "foo/bar" "png" "foo" "baz" # will preview a STL file at foo/bar/foo-bar-baz.png
+#
+# @param filepath - The path of the SCAD file to preview.
+# @param destpath - The path to the output folder.
+# @param extension - The file extension for the ouput file.
+# @param prefix - A prefix to add to the output file.
+# @param suffix - A suffix to add to the output file.
+# @param ... - A list of pre-defined variables.
+scadpreview() {
+    local filepath="$1";
+    local filename=$(basename "${filepath}")
+    local outputpath=$(buildpath "$1" "$2" "$3" "$4" "$5")
+    shift $(($# > 5 ? 5 : $#))
+    printmessage "${C_RST}Rendering of ${C_SEL}${filename}${C_RST} to ${C_SEL}${outputpath}"
+    scadcall "${filepath}" "${outputpath}" --preview "renderMode=\"prod\"" "$@"
+}
+
+# Prints the echos from a module.
+#
+# @example
+# scadecho "bar.scad" "foo/bar"             # will preview a STL file at foo/bar/bar.echo
+# scadecho "bar.scad" "foo/bar" "foo"       # will preview a STL file at foo/bar/foo-bar.echo
+# scadecho "bar.scad" "foo/bar" "foo" "baz" # will preview a STL file at foo/bar/foo-bar-baz.echo
+#
+# @param filepath - The path of the SCAD file from which get the echos.
+# @param destpath - The path to the output folder.
+# @param prefix - A prefix to add to the output file.
+# @param suffix - A suffix to add to the output file.
+# @param ... - A list of pre-defined variables.
+scadecho() {
+    local filepath="$1";
     local filename=$(basename "${filepath}")
-    local name=$(scadmodulename "${filepath}")
-    local outputpath="${destpath}/${prefix}${name}${suffix}.${scadout}"
+    local outputpath=$(buildpath "$1" "$2" "${echoext}" "$3" "$4")
+    shift $(($# > 4 ? 4 : $#))
     printmessage "${C_RST}Rendering of ${C_SEL}${filename}${C_RST} to ${C_SEL}${outputpath}"
-    scadcall "${filepath}" "${outputpath}" "renderMode=\"prod\"" "$@"
+    scadcall "${filepath}" "${outputpath}" --preview "renderMode=\"prod\"" "$@"
 }
 
 # Renders the files from a path. Several processes will be spawned at a time to parallelize the rendering and speeds it up.
diff --git a/scripts/utils/slic3r.sh b/scripts/utils/slic3r.sh
index c6d3508..09a6eeb 100644
--- a/scripts/utils/slic3r.sh
+++ b/scripts/utils/slic3r.sh
@@ -2,7 +2,7 @@
 #
 # GPLv3 License
 #
-# Copyright (c) 2020 Jean-Sebastien CONAN
+# Copyright (c) 2020-2022 Jean-Sebastien CONAN
 #
 # This file is part of jsconan/things.
 #
@@ -94,6 +94,28 @@ useprusaslicer() {
     slic3ruse "PrusaSlicer" "2.1"
 }
 
+# Gets the version of the installed Slic3r.
+# Exits with error code E_SLIC3R if not installed.
+#
+# @example
+# slic3rversion     # will display "xxx.xx.xx",
+#
+# slic3rversion "foo" # will display "xxxx.xx", or return E_SLIC3R if not installed
+#
+# @param [slic3r] - The path to the Slic3r command (default "slic3r").
+slic3rversion() {
+    local version
+    local cmd="${slic3rcmd}"
+    if [ "$1" != "" ]; then
+        cmd="$1"
+    fi
+    version="$(${slic3rcmd} --help | egrep -o '[0-9].[0-9]' | head -1 2>&1)"
+    if [ "$?" != "0" ]; then
+        return ${E_SLIC3R}
+    fi
+    echo "${version}"
+}
+
 # Checks if Slic3r is installed.
 # Exits with error code E_SLIC3R if not installed.
 #
@@ -108,7 +130,7 @@ useprusaslicer() {
 #
 # @param [slic3r] - The path to the Slic3r command (default "slic3r").
 slic3rcheck() {
-    local info=
+    local info
     if [ "$1" != "" ]; then
         slic3rcmd="$1"
         info=" [from ${C_SEL}${slic3rcmd}${C_RST}]"
@@ -156,7 +178,7 @@ slic3rconfig() {
     if [ "${slic3rconfigpath}" != "" ]; then
         printmessage "${C_RST}Will slice the models using the config from ${C_SEL}${slic3rconfigpath}${C_RST}"
         if [ ! -f "${configpath}" ]; then
-            printmessage "${C_ERR}Warning! The config for Slic3r does not exist!"
+            printmessage "${C_WRN}Warning! The config for Slic3r does not exist!"
         fi
     else
         printmessage "${C_RST}No config file provided, will slice the models using the default config."
diff --git a/test/core/maths.scad b/test/core/maths.scad
index 84e53b6..6c61d32 100644
--- a/test/core/maths.scad
+++ b/test/core/maths.scad
@@ -34,7 +34,7 @@ use <../../full.scad>
  * @author jsconan
  */
 module testCoreMaths() {
-    testPackage("core/maths.scad", 32) {
+    testPackage("core/maths.scad", 33) {
         // test core/maths/deg()
         testModule("deg()", 3) {
             testUnit("no parameter", 1) {
@@ -1061,6 +1061,43 @@ module testCoreMaths() {
                 assertEqual(interpolateStep(1, range=range), 9, "Step 1 of external range");
             }
         }
+        // test core/maths/interpolationThreshold()
+        testModule("interpolationThreshold()", 5) {
+            testUnit("wrong value", 4) {
+                assertEqual(interpolationThreshold(), 0, "No parameter given");
+                assertEqual(interpolationThreshold("1", "2", "3", "4", "5"), 0, "String given");
+                assertEqual(interpolationThreshold(true, true, true, true, true), 0, "Booleans given");
+                assertEqual(interpolationThreshold([1], [2], [3], [4], [5]), 0, "Vectors given");
+            }
+            testUnit("no threshold", 5) {
+                assertEqual(interpolationThreshold(0, 4), 0, "Interpolation step 0 from 4 steps");
+                assertEqual(interpolationThreshold(1, 4), 0.25, "Interpolation step 1 from 4 steps");
+                assertEqual(interpolationThreshold(2, 4), 0.5, "Interpolation step 2 from 4 steps");
+                assertEqual(interpolationThreshold(3, 4), 0.75, "Interpolation step 3 from 4 steps");
+                assertEqual(interpolationThreshold(4, 4), 1, "Interpolation step 4 from 4 steps");
+            }
+            testUnit("threshold from computed percentage", 5) {
+                assertEqual(interpolationThreshold(0, 4, .25, .75), 0.25, "Interpolation step 0 from 4 steps");
+                assertEqual(interpolationThreshold(1, 4, .25, .75), 0.375, "Interpolation step 1 from 4 steps");
+                assertEqual(interpolationThreshold(2, 4, .25, .75), 0.5, "Interpolation step 2 from 4 steps");
+                assertEqual(interpolationThreshold(3, 4, .25, .75), 0.625, "Interpolation step 3 from 4 steps");
+                assertEqual(interpolationThreshold(4, 4, .25, .75), 0.75, "Interpolation step 4 from 4 steps");
+            }
+            testUnit("threshold from percentage to compute", 5) {
+                assertEqual(interpolationThreshold(0, 4, 25, 75), 0.25, "Interpolation step 0 from 4 steps");
+                assertEqual(interpolationThreshold(1, 4, 25, 75), 0.375, "Interpolation step 1 from 4 steps");
+                assertEqual(interpolationThreshold(2, 4, 25, 75), 0.5, "Interpolation step 2 from 4 steps");
+                assertEqual(interpolationThreshold(3, 4, 25, 75), 0.625, "Interpolation step 3 from 4 steps");
+                assertEqual(interpolationThreshold(4, 4, 25, 75), 0.75, "Interpolation step 4 from 4 steps");
+            }
+            testUnit("threshold from percentage to compute with scale", 5) {
+                assertEqual(interpolationThreshold(0, 4, 250, 750, 1000), 0.25, "Interpolation step 0 from 4 steps");
+                assertEqual(interpolationThreshold(1, 4, 250, 750, 1000), 0.375, "Interpolation step 1 from 4 steps");
+                assertEqual(interpolationThreshold(2, 4, 250, 750, 1000), 0.5, "Interpolation step 2 from 4 steps");
+                assertEqual(interpolationThreshold(3, 4, 250, 750, 1000), 0.625, "Interpolation step 3 from 4 steps");
+                assertEqual(interpolationThreshold(4, 4, 250, 750, 1000), 0.75, "Interpolation step 4 from 4 steps");
+            }
+        }
     }
 }
 
diff --git a/test/core/version.scad b/test/core/version.scad
index 6b05408..7960733 100644
--- a/test/core/version.scad
+++ b/test/core/version.scad
@@ -45,10 +45,10 @@ module testCoreVersion() {
         // test camelSCAD()
         testModule("camelSCAD()", 2) {
             testUnit("as vector", 1) {
-                assertEqual(camelSCAD(), [1, 5, 0], "The current version of the library is 1.5.0");
+                assertEqual(camelSCAD(), [1, 6, 0], "The current version of the library is 1.6.0");
             }
             testUnit("as string", 1) {
-                assertEqual(camelSCAD(true), "1.5.0", "The current version of the library is 1.5.0");
+                assertEqual(camelSCAD(true), "1.6.0", "The current version of the library is 1.6.0");
             }
         }
     }