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UBL no longer flout's the sacred GCode standard (#6745)

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Also clean up ubl_motion.cpp debug info and fix declaration of cx & cy
This commit is contained in:
Roxy-3D
2017-05-15 16:25:01 -05:00
committed by GitHub
parent c262ea92e0
commit 1fbcbc05f6
4 changed files with 63 additions and 133 deletions
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26
Marlin/G26_Mesh_Validation_Tool.cpp
View File

@@ -88,17 +88,6 @@
* *
* L # Layer Layer height. (Height of nozzle above bed) If not specified .20mm will be used. * L # Layer Layer height. (Height of nozzle above bed) If not specified .20mm will be used.
* *
* Q # Multiplier Retraction Multiplier. Normally not needed. Retraction defaults to 1.0mm and
* un-retraction is at 1.2mm These numbers will be scaled by the specified amount
*
* M # Random Randomize the order that the circles are drawn on the bed. The search for the closest
* undrawn cicle is still done. But the distance to the location for each circle has a
* random number of the size specified added to it. Specifying R50 will give an interesting
* deviation from the normal behaviour on a 10 x 10 Mesh.
* N # Nozzle Used to control the size of nozzle diameter. If not specified, a .4mm nozzle is assumed.
* 'n' can be used instead if your host program does not appreciate you using 'N'.
*
* O # Ooooze How much your nozzle will Ooooze filament while getting in position to print. This * O # Ooooze How much your nozzle will Ooooze filament while getting in position to print. This
* is over kill, but using this parameter will let you get the very first 'circle' perfect * is over kill, but using this parameter will let you get the very first 'circle' perfect
* so you have a trophy to peel off of the bed and hang up to show how perfectly you have your * so you have a trophy to peel off of the bed and hang up to show how perfectly you have your
@@ -111,10 +100,20 @@
* printing the Mesh. You can carefully remove the spent filament with a needle nose * printing the Mesh. You can carefully remove the spent filament with a needle nose
* pliers while holding the LCD Click wheel in a depressed state. * pliers while holding the LCD Click wheel in a depressed state.
* *
* Q # Multiplier Retraction Multiplier. Normally not needed. Retraction defaults to 1.0mm and
* un-retraction is at 1.2mm These numbers will be scaled by the specified amount
*
* R # Repeat Prints the number of patterns given as a parameter, starting at the current location. * R # Repeat Prints the number of patterns given as a parameter, starting at the current location.
* If a parameter isn't given, every point will be printed unless G26 is interrupted. * If a parameter isn't given, every point will be printed unless G26 is interrupted.
* This works the same way that the UBL G29 P4 R parameter works. * This works the same way that the UBL G29 P4 R parameter works.
* *
* S # Nozzle Used to control the size of nozzle diameter. If not specified, a .4mm nozzle is assumed.
*
* U # Random Randomize the order that the circles are drawn on the bed. The search for the closest
* undrawn cicle is still done. But the distance to the location for each circle has a
* random number of the size specified added to it. Specifying S50 will give an interesting
* deviation from the normal behaviour on a 10 x 10 Mesh.
*
* X # X Coord. Specify the starting location of the drawing activity. * X # X Coord. Specify the starting location of the drawing activity.
* *
* Y # Y Coord. Specify the starting location of the drawing activity. * Y # Y Coord. Specify the starting location of the drawing activity.
@@ -686,7 +685,7 @@
} }
} }
if (code_seen('N') || code_seen('n')) { // Warning! Use of 'N' / lowercase flouts established standards. if (code_seen('S')) {
nozzle = code_value_float(); nozzle = code_value_float();
if (!WITHIN(nozzle, 0.1, 1.0)) { if (!WITHIN(nozzle, 0.1, 1.0)) {
SERIAL_PROTOCOLLNPGM("?Specified nozzle size not plausible."); SERIAL_PROTOCOLLNPGM("?Specified nozzle size not plausible.");
@@ -728,9 +727,8 @@
} }
} }
if (code_seen('M')) { // Warning! Use of 'M' flouts established standards. if (code_seen('U')) {
randomSeed(millis()); randomSeed(millis());
// This setting will persist for the next G26
random_deviation = code_has_value() ? code_value_float() : 50.0; random_deviation = code_has_value() ? code_value_float() : 50.0;
} }

2
Marlin/Marlin_main.cpp
View File

@@ -5761,7 +5761,7 @@ inline void gcode_M31() {
/** /**
* M32: Select file and start SD Print * M32: Select file and start SD Print
*/ */
inline void gcode_M32() { inline void gcode_M32() { // Why is M32 allowed to flout the sacred GCode standard?
if (card.sdprinting) if (card.sdprinting)
stepper.synchronize(); stepper.synchronize();

131
Marlin/ubl_G29.cpp
View File

@@ -116,8 +116,7 @@
* invalidate. * invalidate.
* *
* J # Grid * Perform a Grid Based Leveling of the current Mesh using a grid with n points on a side. * J # Grid * Perform a Grid Based Leveling of the current Mesh using a grid with n points on a side.
* * Not specifying a grid size will invoke the 3-Point leveling function.
* j EEPROM Dump This function probably goes away after debug is complete.
* *
* K # Kompare Kompare current Mesh with stored Mesh # replacing current Mesh with the result. This * K # Kompare Kompare current Mesh with stored Mesh # replacing current Mesh with the result. This
* command literally performs a diff between two Meshes. * command literally performs a diff between two Meshes.
@@ -264,8 +263,6 @@
* at a later date. The GCode output can be saved and later replayed by the host software * at a later date. The GCode output can be saved and later replayed by the host software
* to reconstruct the current mesh on another machine. * to reconstruct the current mesh on another machine.
* *
* T 3-Point Perform a 3 Point Bed Leveling on the current Mesh
*
* U Unlevel Perform a probe of the outer perimeter to assist in physically leveling unlevel beds. * U Unlevel Perform a probe of the outer perimeter to assist in physically leveling unlevel beds.
* Only used for G29 P1 O U It will speed up the probing of the edge of the bed. This * Only used for G29 P1 O U It will speed up the probing of the edge of the bed. This
* is useful when the entire bed does not need to be probed because it will be adjusted. * is useful when the entire bed does not need to be probed because it will be adjusted.
@@ -276,12 +273,6 @@
* *
* Y # * * Y Location for this line of commands * Y # * * Y Location for this line of commands
* *
* Z Zero * Probes to set the Z Height of the nozzle. The entire Mesh can be raised or lowered
* by just doing a G29 Z
*
* Z # Zero * The entire Mesh can be raised or lowered to conform with the specified difference.
* zprobe_zoffset is added to the calculation.
*
* *
* Release Notes: * Release Notes:
* You MUST do M502, M500 to initialize the storage. Failure to do this will cause all * You MUST do M502, M500 to initialize the storage. Failure to do this will cause all
@@ -329,7 +320,7 @@
} }
// Don't allow auto-leveling without homing first // Don't allow auto-leveling without homing first
if (!(code_seen('N') && code_value_bool()) && axis_unhomed_error()) // Warning! Use of 'N' flouts established standards. if (axis_unhomed_error())
home_all_axes(); home_all_axes();
if (g29_parameter_parsing()) return; // abort if parsing the simple parameters causes a problem, if (g29_parameter_parsing()) return; // abort if parsing the simple parameters causes a problem,
@@ -353,13 +344,16 @@
} }
if (code_seen('Q')) { if (code_seen('Q')) {
const int test_pattern = code_has_value() ? code_value_int() : -1; const int test_pattern = code_has_value() ? code_value_int() : -99;
if (!WITHIN(test_pattern, 0, 2)) { if (!WITHIN(test_pattern, -1, 2)) {
SERIAL_PROTOCOLLNPGM("Invalid test_pattern value. (0-2)\n"); SERIAL_PROTOCOLLNPGM("Invalid test_pattern value. (0-2)\n");
return; return;
} }
SERIAL_PROTOCOLLNPGM("Loading test_pattern values.\n"); SERIAL_PROTOCOLLNPGM("Loading test_pattern values.\n");
switch (test_pattern) { switch (test_pattern) {
case -1:
g29_eeprom_dump();
break;
case 0: case 0:
for (uint8_t x = 0; x < GRID_MAX_POINTS_X; x++) { // Create a bowl shape - similar to for (uint8_t x = 0; x < GRID_MAX_POINTS_X; x++) { // Create a bowl shape - similar to
for (uint8_t y = 0; y < GRID_MAX_POINTS_Y; y++) { // a poorly calibrated Delta. for (uint8_t y = 0; y < GRID_MAX_POINTS_Y; y++) { // a poorly calibrated Delta.
@@ -385,9 +379,33 @@
} }
if (code_seen('J')) { if (code_seen('J')) {
ubl.save_ubl_active_state_and_disable(); if (grid_size!=0) { // if not 0 it is a normal n x n grid being probed
ubl.tilt_mesh_based_on_probed_grid(code_seen('O') || code_seen('M')); // Warning! Use of 'M' flouts established standards. ubl.save_ubl_active_state_and_disable();
ubl.restore_ubl_active_state_and_leave(); ubl.tilt_mesh_based_on_probed_grid(code_seen('O'));
ubl.restore_ubl_active_state_and_leave();
} else { // grid_size==0 which means a 3-Point leveling has been requested
float z1 = probe_pt(LOGICAL_X_POSITION(UBL_PROBE_PT_1_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_1_Y), false, g29_verbose_level),
z2 = probe_pt(LOGICAL_X_POSITION(UBL_PROBE_PT_2_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_2_Y), false, g29_verbose_level),
z3 = probe_pt(LOGICAL_X_POSITION(UBL_PROBE_PT_3_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_3_Y), true, g29_verbose_level);
if ( isnan(z1) || isnan(z2) || isnan(z3)) { // probe_pt will return NAN if unreachable
SERIAL_ERROR_START;
SERIAL_ERRORLNPGM("Attempt to probe off the bed.");
goto LEAVE;
}
// We need to adjust z1, z2, z3 by the Mesh Height at these points. Just because they are non-zero doesn't mean
// the Mesh is tilted! (We need to compensate each probe point by what the Mesh says that location's height is)
ubl.save_ubl_active_state_and_disable();
z1 -= ubl.get_z_correction(LOGICAL_X_POSITION(UBL_PROBE_PT_1_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_1_Y)) /* + zprobe_zoffset */ ;
z2 -= ubl.get_z_correction(LOGICAL_X_POSITION(UBL_PROBE_PT_2_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_2_Y)) /* + zprobe_zoffset */ ;
z3 -= ubl.get_z_correction(LOGICAL_X_POSITION(UBL_PROBE_PT_3_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_3_Y)) /* + zprobe_zoffset */ ;
do_blocking_move_to_xy(0.5 * (UBL_MESH_MAX_X - (UBL_MESH_MIN_X)), 0.5 * (UBL_MESH_MAX_Y - (UBL_MESH_MIN_Y)));
ubl.tilt_mesh_based_on_3pts(z1, z2, z3);
ubl.restore_ubl_active_state_and_leave();
}
} }
if (code_seen('P')) { if (code_seen('P')) {
@@ -420,7 +438,7 @@
SERIAL_PROTOCOLLNPGM(").\n"); SERIAL_PROTOCOLLNPGM(").\n");
} }
ubl.probe_entire_mesh(x_pos + X_PROBE_OFFSET_FROM_EXTRUDER, y_pos + Y_PROBE_OFFSET_FROM_EXTRUDER, ubl.probe_entire_mesh(x_pos + X_PROBE_OFFSET_FROM_EXTRUDER, y_pos + Y_PROBE_OFFSET_FROM_EXTRUDER,
code_seen('O') || code_seen('M'), code_seen('E'), code_seen('U')); // Warning! Use of 'M' flouts established standards. code_seen('O'), code_seen('E'), code_seen('U'));
break; break;
case 2: { case 2: {
@@ -469,7 +487,7 @@
return; return;
} }
manually_probe_remaining_mesh(x_pos, y_pos, height, card_thickness, code_seen('O') || code_seen('M')); // Warning! Use of 'M' flouts established standards. manually_probe_remaining_mesh(x_pos, y_pos, height, card_thickness, code_seen('O'));
SERIAL_PROTOCOLLNPGM("G29 P2 finished."); SERIAL_PROTOCOLLNPGM("G29 P2 finished.");
} break; } break;
@@ -505,7 +523,7 @@
// //
// Fine Tune (i.e., Edit) the Mesh // Fine Tune (i.e., Edit) the Mesh
// //
fine_tune_mesh(x_pos, y_pos, code_seen('O') || code_seen('M')); // Warning! Use of 'M' flouts established standards. fine_tune_mesh(x_pos, y_pos, code_seen('O'));
break; break;
case 5: ubl.find_mean_mesh_height(); break; case 5: ubl.find_mean_mesh_height(); break;
@@ -515,43 +533,12 @@
} }
if (code_seen('T')) {
float z1 = probe_pt(LOGICAL_X_POSITION(UBL_PROBE_PT_1_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_1_Y), false, g29_verbose_level),
z2 = probe_pt(LOGICAL_X_POSITION(UBL_PROBE_PT_2_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_2_Y), false, g29_verbose_level),
z3 = probe_pt(LOGICAL_X_POSITION(UBL_PROBE_PT_3_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_3_Y), true, g29_verbose_level);
if ( isnan(z1) || isnan(z2) || isnan(z3)) { // probe_pt will return NAN if unreachable
SERIAL_ERROR_START;
SERIAL_ERRORLNPGM("Attempt to probe off the bed.");
goto LEAVE;
}
// We need to adjust z1, z2, z3 by the Mesh Height at these points. Just because they are non-zero doesn't mean
// the Mesh is tilted! (We need to compensate each probe point by what the Mesh says that location's height is)
ubl.save_ubl_active_state_and_disable();
z1 -= ubl.get_z_correction(LOGICAL_X_POSITION(UBL_PROBE_PT_1_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_1_Y)) /* + zprobe_zoffset */ ;
z2 -= ubl.get_z_correction(LOGICAL_X_POSITION(UBL_PROBE_PT_2_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_2_Y)) /* + zprobe_zoffset */ ;
z3 -= ubl.get_z_correction(LOGICAL_X_POSITION(UBL_PROBE_PT_3_X), LOGICAL_Y_POSITION(UBL_PROBE_PT_3_Y)) /* + zprobe_zoffset */ ;
do_blocking_move_to_xy(0.5 * (UBL_MESH_MAX_X - (UBL_MESH_MIN_X)), 0.5 * (UBL_MESH_MAX_Y - (UBL_MESH_MIN_Y)));
ubl.tilt_mesh_based_on_3pts(z1, z2, z3);
ubl.restore_ubl_active_state_and_leave();
}
// //
// Much of the 'What?' command can be eliminated. But until we are fully debugged, it is // Much of the 'What?' command can be eliminated. But until we are fully debugged, it is
// good to have the extra information. Soon... we prune this to just a few items // good to have the extra information. Soon... we prune this to just a few items
// //
if (code_seen('W')) ubl.g29_what_command(); if (code_seen('W')) ubl.g29_what_command();
//
// When we are fully debugged, the EEPROM dump command will get deleted also. But
// right now, it is good to have the extra information. Soon... we prune this.
//
if (code_seen('j')) g29_eeprom_dump(); // Warning! Use of lowercase flouts established standards.
// //
// When we are fully debugged, this may go away. But there are some valid // When we are fully debugged, this may go away. But there are some valid
// use cases for the users. So we can wait and see what to do with it. // use cases for the users. So we can wait and see what to do with it.
@@ -614,9 +601,12 @@
SERIAL_PROTOCOLLNPGM("Done.\n"); SERIAL_PROTOCOLLNPGM("Done.\n");
} }
if (code_seen('O') || code_seen('M')) // Warning! Use of 'M' flouts established standards. if (code_seen('O'))
ubl.display_map(code_has_value() ? code_value_int() : 0); ubl.display_map(code_has_value() ? code_value_int() : 0);
/*
* This code may not be needed... Prepare for its removal...
*
if (code_seen('Z')) { if (code_seen('Z')) {
if (code_has_value()) if (code_has_value())
ubl.state.z_offset = code_value_float(); // do the simple case. Just lock in the specified value ubl.state.z_offset = code_value_float(); // do the simple case. Just lock in the specified value
@@ -669,6 +659,7 @@
ubl.restore_ubl_active_state_and_leave(); ubl.restore_ubl_active_state_and_leave();
} }
} }
*/
LEAVE: LEAVE:
@@ -1069,8 +1060,8 @@
} }
if (code_seen('J')) { if (code_seen('J')) {
grid_size = code_has_value() ? code_value_int() : 3; grid_size = code_has_value() ? code_value_int() : 0;
if (!WITHIN(grid_size, 2, 9)) { if (grid_size!=0 && !WITHIN(grid_size, 2, 9)) {
SERIAL_PROTOCOLLNPGM("?Invalid grid size (J) specified (2-9).\n"); SERIAL_PROTOCOLLNPGM("?Invalid grid size (J) specified (2-9).\n");
err_flag = true; err_flag = true;
} }
@@ -1126,43 +1117,9 @@
SERIAL_PROTOCOLLNPGM("Invalid map type.\n"); SERIAL_PROTOCOLLNPGM("Invalid map type.\n");
return UBL_ERR; return UBL_ERR;
} }
// Check if a map type was specified
if (code_seen('M')) { // Warning! Use of 'M' flouts established standards.
map_type = code_has_value() ? code_value_int() : 0;
if (!WITHIN(map_type, 0, 1)) {
SERIAL_PROTOCOLLNPGM("Invalid map type.\n");
return UBL_ERR;
}
}
return UBL_OK; return UBL_OK;
} }
/**
* This function goes away after G29 debug is complete. But for right now, it is a handy
* routine to dump binary data structures.
*/
/*
void dump(char * const str, const float &f) {
char *ptr;
SERIAL_PROTOCOL(str);
SERIAL_PROTOCOL_F(f, 8);
SERIAL_PROTOCOLPGM(" ");
ptr = (char*)&f;
for (uint8_t i = 0; i < 4; i++)
SERIAL_PROTOCOLPAIR(" ", hex_byte(*ptr++));
SERIAL_PROTOCOLPAIR(" isnan()=", isnan(f));
SERIAL_PROTOCOLPAIR(" isinf()=", isinf(f));
if (f == -INFINITY)
SERIAL_PROTOCOLPGM(" Minus Infinity detected.");
SERIAL_EOL;
}
//*/
static int ubl_state_at_invocation = 0, static int ubl_state_at_invocation = 0,
ubl_state_recursion_chk = 0; ubl_state_recursion_chk = 0;

37
Marlin/ubl_motion.cpp
View File

@@ -55,12 +55,8 @@
dy = current_position[Y_AXIS] - destination[Y_AXIS], dy = current_position[Y_AXIS] - destination[Y_AXIS],
xy_dist = HYPOT(dx, dy); xy_dist = HYPOT(dx, dy);
if (xy_dist == 0.0) { if (xy_dist == 0.0)
return; return;
//SERIAL_ECHOPGM(" FPMM=");
//const float fpmm = de / xy_dist;
//SERIAL_PROTOCOL_F(fpmm, 6);
}
else { else {
SERIAL_ECHOPGM(" fpmm="); SERIAL_ECHOPGM(" fpmm=");
const float fpmm = de / xy_dist; const float fpmm = de / xy_dist;
@@ -276,16 +272,7 @@
*/ */
if (y != start[Y_AXIS]) { if (y != start[Y_AXIS]) {
if (!inf_normalized_flag) { if (!inf_normalized_flag) {
//on_axis_distance = y - start[Y_AXIS];
on_axis_distance = use_x_dist ? x - start[X_AXIS] : y - start[Y_AXIS]; on_axis_distance = use_x_dist ? x - start[X_AXIS] : y - start[Y_AXIS];
//on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
//on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];
//on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
//on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];
e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist; e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist;
z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist; z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist;
} }
@@ -350,13 +337,7 @@
*/ */
if (x != start[X_AXIS]) { if (x != start[X_AXIS]) {
if (!inf_normalized_flag) { if (!inf_normalized_flag) {
//on_axis_distance = x - start[X_AXIS];
on_axis_distance = use_x_dist ? x - start[X_AXIS] : y - start[Y_AXIS]; on_axis_distance = use_x_dist ? x - start[X_AXIS] : y - start[Y_AXIS];
//on_axis_distance = use_x_dist ? next_mesh_line_x - start[X_AXIS] : y - start[Y_AXIS];
//on_axis_distance = use_x_dist ? x - start[X_AXIS] : next_mesh_line_y - start[Y_AXIS];
e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist; // is based on X or Y because this is a horizontal move e_position = start[E_AXIS] + on_axis_distance * e_normalized_dist; // is based on X or Y because this is a horizontal move
z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist; z_position = start[Z_AXIS] + on_axis_distance * z_normalized_dist;
} }
@@ -613,20 +594,14 @@
cell_xi = constrain(cell_xi, 0, (GRID_MAX_POINTS_X) - 1); cell_xi = constrain(cell_xi, 0, (GRID_MAX_POINTS_X) - 1);
cell_yi = constrain(cell_yi, 0, (GRID_MAX_POINTS_Y) - 1); cell_yi = constrain(cell_yi, 0, (GRID_MAX_POINTS_Y) - 1);
// float x0 = (UBL_MESH_MIN_X) + ((MESH_X_DIST) * cell_xi ); // lower left cell corner
// float y0 = (UBL_MESH_MIN_Y) + ((MESH_Y_DIST) * cell_yi ); // lower left cell corner
// float x1 = x0 + MESH_X_DIST; // upper right cell corner
// float y1 = y0 + MESH_Y_DIST; // upper right cell corner
const float x0 = pgm_read_float(&(ubl.mesh_index_to_xpos[cell_xi ])), // 64 byte table lookup avoids mul+add const float x0 = pgm_read_float(&(ubl.mesh_index_to_xpos[cell_xi ])), // 64 byte table lookup avoids mul+add
y0 = pgm_read_float(&(ubl.mesh_index_to_ypos[cell_yi ])), // 64 byte table lookup avoids mul+add y0 = pgm_read_float(&(ubl.mesh_index_to_ypos[cell_yi ])), // 64 byte table lookup avoids mul+add
x1 = pgm_read_float(&(ubl.mesh_index_to_xpos[cell_xi+1])), // 64 byte table lookup avoids mul+add x1 = pgm_read_float(&(ubl.mesh_index_to_xpos[cell_xi+1])), // 64 byte table lookup avoids mul+add
y1 = pgm_read_float(&(ubl.mesh_index_to_ypos[cell_yi+1])), // 64 byte table lookup avoids mul+add y1 = pgm_read_float(&(ubl.mesh_index_to_ypos[cell_yi+1])); // 64 byte table lookup avoids mul+add
cx = rx - x0, // cell-relative x float cx = rx - x0, // cell-relative x
cy = ry - y0; // cell-relative y cy = ry - y0; // cell-relative y
z_x0y0 = ubl.z_values[cell_xi ][cell_yi ], // z at lower left corner
float z_x0y0 = ubl.z_values[cell_xi ][cell_yi ], // z at lower left corner
z_x1y0 = ubl.z_values[cell_xi+1][cell_yi ], // z at upper left corner z_x1y0 = ubl.z_values[cell_xi+1][cell_yi ], // z at upper left corner
z_x0y1 = ubl.z_values[cell_xi ][cell_yi+1], // z at lower right corner z_x0y1 = ubl.z_values[cell_xi ][cell_yi+1], // z at lower right corner
z_x1y1 = ubl.z_values[cell_xi+1][cell_yi+1]; // z at upper right corner z_x1y1 = ubl.z_values[cell_xi+1][cell_yi+1]; // z at upper right corner