diff --git a/NAMESPACE b/NAMESPACE
index 8b647632..0d44f360 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -185,6 +185,7 @@ export(tm_minimap)
 export(tm_mouse_coordinates)
 export(tm_mv)
 export(tm_mv_dim)
+export(tm_mv_shape_vars)
 export(tm_options)
 export(tm_place_legends_bottom)
 export(tm_place_legends_inside)
diff --git a/R/step1_helper_facets.R b/R/step1_helper_facets.R
index a13f354f..5121b93e 100644
--- a/R/step1_helper_facets.R
+++ b/R/step1_helper_facets.R
@@ -83,8 +83,15 @@ step1_rearrange_facets = function(tmo, o) {
 		precheck_aes = function(a, layer, shpvars, args) {
 			within(a, {
 				
-				if (inherits(value, "tmapDimVars")) {
-					if (!(value$x %in% smeta$dims)) stop("Unknown dimension in tm_dim_vars", call. = FALSE)
+				if (inherits(value, "tmapDimVars") || (inherits(value, "tmapMVShpVars") && length(shpvars) == 1L && value$n >= 1)) {
+					if (inherits(value, "tmapDimVars")) {
+						if (!(value$x %in% smeta$dims)) stop("Unknown dimension in tm_dim_vars", call. = FALSE)
+					} else {
+						value = list(x = smeta$dims[1], values = {
+							if (is.na(value$n)) smeta$dims_vals[[1]] else smeta$dims_vals[[1]][1L:value$n]
+						})
+					}
+					
 					split_stars_dim = value$x
 					if (!all(value$values %in% smeta$dims_vals[[split_stars_dim]])) stop("Unknown values in tm_dim_vars", call. = FALSE)
 					
@@ -110,7 +117,21 @@ step1_rearrange_facets = function(tmo, o) {
 						if (!is.list(value_orig)) value = list(value_orig)
 						names(value) = sapply(value, "[", 1)
 					} else if (inherits(value, "tmapShpVars")) {
-						value = as.list(shpvars)
+						if (is.na(value$n)) {
+							value = as.list(shpvars)
+						} else {
+							if (length(shpvars) < value$n) {
+								stop("tm_shape_vars defined for n = ", value$n, " while there are only ", length(shpvars), " variables", call. = FALSE)
+							}
+							value = as.list(shpvars[1L:value$n])
+						}
+					} else if (inherits(value, "tmapMVShpVars")) {
+						if (is.na(value$n)) {
+							value = list(shpvars)
+						} else {
+							if (length(shpvars) < value$n) stop("tm_shape_vars specified with n = ", value$n, " but there are only ", length(shpvars), " variables available", call. = FALSE)
+							value = list(shpvars[1L:value$n])
+						}
 					} else {
 						value_orig = value
 						#value = lapply(value_orig, make.names)
diff --git a/R/step2_helper_data.R b/R/step2_helper_data.R
index 2097df80..7d9e60b6 100644
--- a/R/step2_helper_data.R
+++ b/R/step2_helper_data.R
@@ -159,21 +159,6 @@ getdts = function(aes, unm, p, q, o, dt, shpvars, layer, mfun, args, plot.order)
 			aes$data_vars = FALSE
 		}
 			
-			# 
-			# List of 10
-			# $ scale        :List of 1
-			# ..- attr(*, "class")= chr [1:3] "tm_scale_auto" "tm_scale" "list"
-			# $ legend       :List of 65
-			# ..- attr(*, "class")= chr [1:2] "tm_legend_standard_portrait" "list"
-			# $ chart        :List of 36
-			# ..- attr(*, "class")= chr [1:4] "tm_chart_none" "tm_chart" "tm_component" "list"
-			# $ o            :List of 343
-			# $ aes          : chr "fill"
-			# $ layer        : chr "polygons"
-			# $ layer_args   : list()
-			# $ sortRev      : logi NA
-			# $ bypass_ord   : logi FALSE
-			# $ submit_legend: logi TRUE
 		if (!aes$data_vars && !aes$geo_vars) {
 			#cat("step2_grp_lyr_aes_const", unm," \n")
 			# constant values (take first value (of possible tm_mv per facet)
diff --git a/R/tm_layers_rgb.R b/R/tm_layers_rgb.R
index d619ddde..82919b3c 100644
--- a/R/tm_layers_rgb.R
+++ b/R/tm_layers_rgb.R
@@ -13,9 +13,9 @@ opt_tm_rgb = function(interpolate = FALSE) {
 #' @param col,col.scale,col.legend,col.chart,col.free Visual variable that determines
 #'   the col color. `col` is a multivariate variable, with 3 (`tm_rgb`) or 4 (`tm_rgba`) numeric data variables. These can be specified via [tm_mv()] or [tm_mv_dim()]
 #' @param options options passed on to the corresponding `opt_<layer_function>` function 
-
+#' @example ./examples/tm_rgb.R 
 #' @export
-tm_rgb = function(col = tm_mv(1:3),
+tm_rgb = function(col = tm_mv_shape_vars(3),
 				  col.scale = tm_scale_rgb(),
 				  col.legend = tm_legend(),
 				  col.chart = tm_chart_none(),
@@ -26,7 +26,7 @@ tm_rgb = function(col = tm_mv(1:3),
 
 #' @rdname tm_rgb
 #' @export
-tm_rgba = function(col = tm_mv(1:4),
+tm_rgba = function(col = tm_mv_shape_vars(4),
 				  col.scale = tm_scale_rgba(),
 				  col.legend = tm_legend(),
 				  col.chart = tm_chart_none(),
diff --git a/R/tm_scale_.R b/R/tm_scale_.R
index 657ec834..2f8d5b72 100644
--- a/R/tm_scale_.R
+++ b/R/tm_scale_.R
@@ -11,9 +11,18 @@ tm_const = function() {
 #' 
 #' tmap function to specify all variables in the shape object
 #' 
+#' @param n the first `n` shape variables are used
+#' @rdname tm_shape_vars
 #' @export
-tm_shape_vars = function() {
-	structure(list(), class = c("tm_shape_vars", "list"))
+tm_shape_vars = function(n = NA) {
+	structure(list(n = n), class = c("tm_shape_vars", "list"))
+}
+
+#' @rdname tm_shape_vars
+#' @name tm_mv_shape_vars
+#' @export
+tm_mv_shape_vars = function(n = NA) {
+	structure(list(n = n), class = c("tm_mv_shape_vars", "list"))
 }
 
 #' Scales: automatic scale
diff --git a/R/tmapScale_.R b/R/tmapScale_.R
index eaa75271..b682e742 100644
--- a/R/tmapScale_.R
+++ b/R/tmapScale_.R
@@ -21,7 +21,8 @@ tm_mv_dim = function(x, values) {
 
 tmapVars = function(x) {
 	if (inherits(x, "tmapOption")) return(x)
-	if (inherits(x, "tm_shape_vars")) return(structure(list(), class = "tmapShpVars"))
+	if (inherits(x, "tm_shape_vars")) return(structure(list(n = x$n), class = "tmapShpVars"))
+	if (inherits(x, "tm_mv_shape_vars")) return(structure(list(n = x$n), class = "tmapMVShpVars"))
 	if (inherits(x, "tmapDimVars")) return(x)
 	
 	cls = if (inherits(x, "AsIs")) "tmapAsIs" else if (inherits(x, "tmapUsrCls")) "tmapUsrCls" else "tmapVars"
diff --git a/examples/tm_rgb.R b/examples/tm_rgb.R
index 29fad091..7a380d72 100644
--- a/examples/tm_rgb.R
+++ b/examples/tm_rgb.R
@@ -1,31 +1,31 @@
+require(stars)
 file = system.file("tif/L7_ETMs.tif", package = "stars")
 
 L7 = stars::read_stars(file)
 
-# not working yet #819
 tm_shape(L7) +
 	tm_rgb()
 
+\dontrun{
+# the previous example was a shortcut of this call
 tm_shape(L7) +
 	tm_rgb(col = tm_mv_dim("band", 1:3))
 
-tm_shape(L7) +
-	tm_rgba(col = tm_mv_dim("band", 1:4))
-
-library(stars)
+# alternative format: using a stars dimension instead of attributes
 L7_alt = split(L7, "band")
-
-# not working yet #819
 tm_shape(L7_alt) +
 	tm_rgb()
 
 tm_shape(L7_alt) +
 	tm_rgb(col = tm_mv("X1", "X2", "X3"))
 
-tm_shape(L7_alt) +
-	tm_rgb(col = tm_mv(1:3))
-
-L7_terra = terra::rast(file)
-
-tm_shape(L7_terra) +
-	tm_rgb(col = do.call(tm_mv, as.list(names(L7_terra)[1:3])))
+if (requireNamespace("terra")) {
+	L7_terra = terra::rast(file)
+	
+	tm_shape(L7_terra) +
+		tm_rgb()
+	
+	tm_shape(L7_terra) +
+		tm_rgb(tm_mv(names(L7_terra)[1:3]))
+}
+}
diff --git a/man/tm_rgb.Rd b/man/tm_rgb.Rd
index b61045c6..1f7aaeb6 100644
--- a/man/tm_rgb.Rd
+++ b/man/tm_rgb.Rd
@@ -9,7 +9,7 @@
 opt_tm_rgb(interpolate = FALSE)
 
 tm_rgb(
-  col = tm_mv(1:3),
+  col = tm_mv_shape_vars(3),
   col.scale = tm_scale_rgb(),
   col.legend = tm_legend(),
   col.chart = tm_chart_none(),
@@ -18,7 +18,7 @@ tm_rgb(
 )
 
 tm_rgba(
-  col = tm_mv(1:4),
+  col = tm_mv_shape_vars(4),
   col.scale = tm_scale_rgba(),
   col.legend = tm_legend(),
   col.chart = tm_chart_none(),
@@ -37,3 +37,36 @@ the col color. \code{col} is a multivariate variable, with 3 (\code{tm_rgb}) or
 \description{
 Map layer that an rgb image.. The used (multivariate) visual variable is \code{col}, which should be specified with 3 or 4 variables for \code{tm_rgb} and \code{tm_rgba} respectively. The first three correspond to the red, green, and blue channels. The optional fourth is the alpha transparency channel.
 }
+\examples{
+require(stars)
+file = system.file("tif/L7_ETMs.tif", package = "stars")
+
+L7 = stars::read_stars(file)
+
+tm_shape(L7) +
+	tm_rgb()
+
+\dontrun{
+# the previous example was a shortcut of this call
+tm_shape(L7) +
+	tm_rgb(col = tm_mv_dim("band", 1:3))
+
+# alternative format: using a stars dimension instead of attributes
+L7_alt = split(L7, "band")
+tm_shape(L7_alt) +
+	tm_rgb()
+
+tm_shape(L7_alt) +
+	tm_rgb(col = tm_mv("X1", "X2", "X3"))
+
+if (requireNamespace("terra")) {
+	L7_terra = terra::rast(file)
+	
+	tm_shape(L7_terra) +
+		tm_rgb()
+	
+	tm_shape(L7_terra) +
+		tm_rgb(tm_mv(names(L7_terra)[1:3]))
+}
+}
+}
diff --git a/man/tm_shape_vars.Rd b/man/tm_shape_vars.Rd
index 48d6cd54..c0d08f8a 100644
--- a/man/tm_shape_vars.Rd
+++ b/man/tm_shape_vars.Rd
@@ -2,9 +2,15 @@
 % Please edit documentation in R/tm_scale_.R
 \name{tm_shape_vars}
 \alias{tm_shape_vars}
+\alias{tm_mv_shape_vars}
 \title{tmap function to specify all variables in the shape object}
 \usage{
-tm_shape_vars()
+tm_shape_vars(n = NA)
+
+tm_mv_shape_vars(n = NA)
+}
+\arguments{
+\item{n}{the first \code{n} shape variables are used}
 }
 \description{
 tmap function to specify all variables in the shape object