[Lookid]

Hello,

just trying some stuff with blockmesh.

To confirm, it's impossible to make a single-block like in the picutre, right? Even if spline edges are properly defined. I get the inside-out error whatever blocking I'm using.

blockMeshDict (with all points defined as in the picture):

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  3.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //


convertToMeters 0.001;

vertices
(

( 268.582210142 -39.6137430734 0.0 ) 
( -20.5142598058 -20.4979302521 0.0 ) 
( -20.4979302521 20.5142598058 0.0 ) 
( 268.613743073 39.5822101419 0.0 ) 
( 189.386256927 -39.5822101419 0.0 ) 
( 20.4979302521 -20.5142598058 0.0 ) 
( 20.5142598058 20.4979302521 0.0 ) 
( 189.417789858 39.6137430734 0.0 ) 

);

blocks
(

hex (0 3 7 4 1 2 6 5) (20 20 20) simpleGrading (1 1 1)

);

edges
(

spline 0 4 ( (255.874573542 -44.6428760098 0.0) (242.594542481 -47.8622854626 0.0) (228.980580821 -48.9999939825 0.0) (215.367564750 -47.8508776458 0.0) (202.090068477 -44.6210050005 0.0) ) 
spline 4 7 ( (184.357123990 -26.8745735423 0.0) (181.137714537 -13.5945424809 0.0) (180.000006017 0.0194191788592 0.0) (181.149122354 13.6324352502 0.0) (184.378995000 26.9099315233 0.0) ) 
spline 7 3 ( (202.125426458 44.6428760098 0.0) (215.405457519 47.8622854626 0.0) (229.019419179 48.9999939825 0.0) (242.632435250 47.8508776458 0.0) (255.909931523 44.6210050005 0.0) ) 
spline 3 0 ( (273.642876010 26.8745735423 0.0) (276.862285463 13.5945424809 0.0) (277.999993983 -0.0194191788592 0.0) (276.850877646 -13.6324352502 0.0) (273.621005000 -26.9099315233 0.0) ) 
spline 5 1 ( (13.8004171310 -22.4143605580 0.0) (6.93971084750 -23.5948447110 0.0) (-0.009542618588 -23.9999968518 0.0) (-6.95846613581 -23.5891963112 0.0) (-13.8182347492 -22.4032696527 0.0) ) 
spline 1 2 ( (-22.4143605580 -13.8004171310 0.0) (-23.5948447110 -6.93971084750 0.0) (-23.9999968518 0.00954261858799 0.0) (-23.5891963112 6.95846613581 0.0) (-22.4032696527 13.8182347492 0.0) ) 
spline 2 6 ( (-13.8004171310 22.4143605580 0.0) (-6.93971084750 23.5948447110 0.0) (0.00954261858799 23.9999968518 0.0) (6.95846613581 23.5891963112 0.0) (13.8182347492 22.4032696527 0.0) ) 
spline 6 5 ( (22.4143605580 13.8004171310 0.0) (23.5948447110 6.93971084750 0.0) (23.9999968518 -0.00954261858799 0.0) (23.5891963112 -6.95846613581 0.0) (22.4032696527 -13.8182347492 0.0) ) 
spline 1 0 ( (-0.148456682308 -22.1043412349 71.0653616454) (52.5438895134 -25.9391805246 122.776006529) (123.894913297 -30.6367233304 141.556360260) (195.233074775 -35.0755852161 122.631934858) (248.067767194 -38.3411798124 71.0089257473) ) 
spline 5 4 ( (32.9116859445 -21.6929465404 41.0814093398) (63.7700958775 -24.7685721689 70.7935746998) (105.095058166 -29.0654396086 81.6726970517) (146.393109715 -33.7892987772 70.8954191362) (177.056523357 -37.8255199041 41.1098995999) ) 
spline 6 7 ( (32.9294869846 21.6801460586 41.0849753298) (63.7908606402 24.7646322807 70.7988739413) (105.118804416 29.0730991798 81.6779465969) (146.419578872 33.8085807103 70.9000282376) (177.086206232 37.8536196377 41.1132134471) ) 
spline 2 3 ( (-0.131704011871 22.1171276741 71.0694599908) (52.5631069512 25.9430893685 122.783777746) (123.918561288 30.6290838194 141.565320601) (195.261001764 35.0564240395 122.639185222) (248.098431670 38.3131804627 71.0128165282) ) 

);

boundary
(
 
);

mergePatchPairs
(
);

// ************************************************************************* //

[Lookid]

So blockMesh first draws straight edges with the block you defined and see if it's valid block.

example of a valid block, but almost not valid:
image_2021-01-16_124133.png

If not, it stops there. So, if all points are on the same place, invalid block.

On the other hand it means you can do that from a single block, provided the "base-block" is valid:
image_2021-01-16_124144.png


Pretty sure I could have figured this out if I read the documentation though...