recastnavigation region IDs in compact heightfield are alsways 0 - need to identify tile border

Hi all,

i am analysing the compact heightfield used during the NavMesh creation process and need to find spans liying on a tile-border.
I grab the data here:

I walk through all spans like this:

for (int32 y = 0; y < h; ++y) {
        for (int32 x = 0; x < w; ++x) {
            const float fx = chf->bmin[0] + x*cs;
            const float fz = chf->bmin[2] + y*cs;
            const rcCompactCell& c = chf->cells[x+y*w];
            for (int32 i = (int)c.index, ni = (int)(c.index+c.count); i < ni; ++i) {
                // chf->spans*.reg is always 0

Like stated in the code chf->spans*.reg is always 0 so i wonder how i could find out if a span is on a tile-border? Side note: Mikko told me that i access the data the right way.

All help is very welcome, i am running out of ideas :frowning:
Thanks in advance,