Invalid mesh topology

Hello. In my model I need to set nodes at a certain distance. May I do this using meshing? I didn't find any solution for this using meshing therefore I tried to draw lines which intersections would represent the nodes I need. The problem is that when I am using "F2" key to define lines coordinates, FEFLOW crashes at meshing, using Grid Builder method. When I add lines using mouse click, it works. I saw that this topic was posted 5 years ago, but no solution was found. There is any way I can obtain a certain distance between nodes, rather than using lines?

Also, Triangle and Advance Front are not helping me if Grid Builder doesn't work, or maybe I don't know how to use them.

Thank you!

To set nodes at a certain distance, you can have vertices on a line (either imported or set in FEFLOW by clicking on the line  - the trick is then using F2 to fix the coordinates). The danger of your method only using F2 is that FEFLOW might not always recognize that the coordinates you set are exactly on the existing line, thus not subdividing this line and subsequently ending up with a vertex very close to the line. Gridbuilder is in general less tolerant of such conditions than Triangle. Advancing front will not help you as it does not use the lines and points you put at all (only polygons).

Sorry If I don't get it, but do you mean like in the image below?

I made the lines using short lines of 1 meter. On the left side is before while on the right side is after I connect the dots. Even like this, it doesn't work.

Only when I draw connection lines without using the dots, by mouse clicking, then it works. I will ad the image on next one. Another way is to find a good refinement of the lines to obtain nodes at each 0.25 or 0.5 m, but it's not perfect.

This is the image.

The main idea is that I need a certain distance between the node in all three directions. For example If I model a diaphragm wall having 6m length, 1.2m wide and 15m depth, I need to have nodes at 10cm from the edges, at 1m distance on one face and also at every meter in depth.

For example, in the image below, W - 1.2m, L - 6m, sp - 1m, c - 0.1m, D - 15m. I solve depth by defining slices, but what about the others?

Thank you!

I managed to succeed by using Triangle along with points. There is need for setting small point target size with a small graduation not distort the straight lines representing the walls contour. The nodes can be furthermore connected with lines, for an easily find the center point.

I think I'd use polygons for this, splitting the polygon for the diaphragm wall into smaller pieces by using the 'split polygons' tool (once again here, I'd first split them roughly at the right place, then move the node by using F2).