GiD forum

Hi all,

I have a complex geometry for which I want to generate planar surfaces automatically. By using the command of NURBS surface and 'automate', I need to enter the number of lines necessary to generate the surfaces. When I want to generate surfaces with 6 lines for example, it creates also NURBS surfaces defined by 6 lines that are not in the same plan which is undesired ... How can I avoid this and generate only planar surfaces please ?

Thanks,
Samia

unfortunately nowadays is not possible to prevent the creation of non planar shaped surface in the procedure that create NURBS surfaces 'automatic of n sides' .
I don't remember also any current tool or filter to easily select the non-planar (with a tolerance) surfaces.

We can study to add these features in new versions.
Now you must manually identify and delete the 'curved surfaces' that you don't want.

You can also create a user macro in Tcl scripting language to filter them (the GiD_Info parametric surface $id maincurvature or derivatives will aid you to detect curved surfaces)

Thanks for the answer, I will try the user macro!
Samia

Thanks for the answer,

When trying to create the user macro and use the command line with -np-, GiD doesn't react to the commands I enter ... The most basic command I tried is "-np- GiD_Info Project". It doesn't return any error message, but it doesn't return the result neither .. How can I fix this ?

I also checked the command "GiD_Geometry delete surface <args>" where <args>: num numa:numb buma:layer:layer_name. Could you please explain what is the meaning of this parameter <args> ?

Finally, I found an example of the command GiD_Info parametric Surface : "GiD_Info parametric line 26 deriv_t 0.25" I don't understand to which parameter corresponds the 0.25 ? Isn't it supposed to be something like "xyz" or "uv" ?

Thanks,
Samia

a command like will get the information of the project, but nothing is done with this data, probably do you want to be shown in a window.
we have for example a short name of a Tcl procedure that show a text in a window, this procedure is simply named W
try this: (the [] are to evaluate a Tcl command, it is Tcl syntax)

About
GiD_Geometry delete surface <args>
where <args>: num | numa:numb | layer:layer_name.
args is a variable list of arguments, there could be different amount of arguments, with the explained meaning
e.g will delete the surface id=3 will delete the surfaces with number between 3 and 5 (included) will delete the layers that are assigned to the layer named 'hello'

and about GiD_Info parametric it allow ask for different things of a curve or surface (the 3D point from its parameter, or the parameter closest to a 3D point, or derivatives and more... (as is explained in the GiD customization manual)
e.g will return a list with the 3 values dx dy dz of the derivative of the curve number 26 at the parameter value=0.25 (GiD curves are parametrized from 0.0 to 1.0)
Note: the parameter 0.25 is not equal to the 25% of the curve lenght. Parametrizations could be very non-uniform