Enable the ability to align the orientation of the plane or water primitives to the current camera view. So, whatever the camera view is, the plane or water would appear horizontal. When enabled, there would be a 'pitch' slider allowing to set the 'slope' of the plane towards or away from the camera.
I have the following scene, for which I'd like to set a water plane somewhere towards the bottom of the image, but I've had a very hard time trying to work out how to set the orientation of the water so it actually displays as I'd expect :
# Mandelbulber settings file
# version 2.11
# only modified parameters
[main_parameters]
ambient_occlusion_enabled true;
camera -0.1604361919527667 -0.08946333362865883 -0.1891149412365135;
camera_distance_to_target 1.101839065551758;
camera_rotation -47.63981307687165 9.873006465211107 -180;
camera_top 0.1266995329085963 0.1155312273091807 -0.9851902171038738;
check_for_bailout_3 false;
detail_level 4;
DOF_enabled true;
DOF_focus 0.0003057379508391023;
DOF_number_of_passes 2;
DOF_radius 4;
flight_last_to_render 0;
fog_color_1 8400 6900 4c00;
fog_color_2 ce00 c100 be00;
formula_1 108;
formula_2 1044;
formula_material_id 2;
formula_stop_iteration_2 2;
fov 0.5;
fractal_enable_3 false;
fractal_enable_4 false;
glow_enabled false;
hybrid_fractal_enable true;
initial_waxis -0.1;
julia_c -11 -14 -11;
keyframe_last_to_render 0;
mat1_coloring_palette_offset 8.06;
mat1_coloring_speed 4;
mat1_is_defined true;
mat1_surface_color_palette c08080 ff0000 c0c000 00ff00 00c0c0 0000ff c08cc0 ffaa00 404040 808080;
mat2_displacement_texture_height 0.05;
mat2_file_color_texture C:UsersxxxxxxxxOneDrivePicturesTexturesSandstone_Wall_1.jpg;
mat2_file_displacement_texture C:UsersxxxxxxxxOneDrivePicturesTexturesSandstone_Wall_1.jpg;
mat2_is_defined true;
mat2_name Sandstone;
mat2_specular 0.1;
mat2_specular_width 5;
mat2_texture_mapping_type 0;
mat2_texture_scale 0.2 0.2 0.2;
mat2_use_color_texture true;
mat2_use_colors_from_palette false;
raytraced_reflections true;
target 0.6416810677390673 0.6419489244175326 -0.0001881383201286009;
volumetric_fog_colour_1_distance 1.562927106316925e-05;
volumetric_fog_colour_2_distance 3.12585421263385e-05;
volumetric_fog_distance_factor 3.12585421263385e-05;
volumetric_fog_enabled true;
[fractal_1]
analyticDE_scale_1 1.1;
transf_addition_constant_0000 0 0 0 0.1;
[fractal_2]
analyticDE_scale_1 1.1;
mandelbox_rotation_main 11 6 3;
transf_constant_multiplier_111 -0.5 -0.4 -0.5;
transf_function_enabledM false;
transf_function_enabledX_false true;
transf_offset_000 1 1.3 0.5;
transf_rotation2 0 0 19;
transf_scale 0.149007;
transf_start_iterations_P 250;
transf_stop_iterations_P1 3;
I hope I've been clear enough with my requirement, but please let me know if I can provide further detail.