Help on FLOW along Surface technique

Hello everyone.

I need to flow this polysurface pattern along a surface which is for a terrain street/path
I dont understand what I am doing wrong. I was able to accomplish other surfaces but this is getting me nerves

Any help would be very nice.
best regards
tutorial teste.3dm (2.2 MB)

Hi Antonio - the target surface should have UVs that follow the shape as in the attached file.

tutorial teste_PG.3dm (371.4 KB)


Hi there…
Thanks a lot Pascal for spend your time help me here.

Can you please send me to a tutorial link were I can study the UVs.
Or can you teach me how can I change UVs for better accurate Flow Objects?

best regards

Hi Antonio - to create the target surface in this case I exploded then made a Sweep2 from the red curves - I used AddSlash in the Sweep dialog a number of times to line up the isocurves to go straight across and not diagonal in the short direction. When it looked OK, I finished the Sweep2 command and the used Rebuild on the result, with lots of points - this results in a much more evenly distributed UV and therefore more accurate Flow than with the result directly from Sweep2.


I see what you mean…
I have accomplished the SWEEP2 + SPLASH and REBUILD… let see if I can flow this pattern.

If I understand well… The technique behind the FLOW is to achieve the perfect UVs and direction from the desire surface, and then make the flow, right?

If I don’t have an accurate surface for the FLOW option, it will always result an incorrect Flowing

Hi Pascal…
I achieve the surface UVs… but i miss something that i can not made the Flow above that terrain surface… Not the flat one. The other.

FLOW incorrect.3dm (6.3 MB)

On the rebuilt surface that @pascal had you create, with the large number of UV’s, you need to switch the surface directions so that U’s become V’s and V’s become U’s. To do this, use the Direction command (type Dir). Choose the Swap UV option. After this is done, try the Flow Along Surface command (not Flow), and I think you will find that it now works. The problem was that your original base surface’s UV’s were opposite your target surface’s UV’s. When you ran the Dir/Swap UVs command, both base surface and target surface U’s and V’s now run in the same corresponding directions, and the results of the Flow look correct. Actually, you could get the correct Flow results if you used the Dir command on either the base or target surface. The net result would be that after running Dir on either, the U’s and V’s would match and Flow Along Surface would work as expected.

Best regards,


I have been away for a week.
I will try as you say