On 15.12.2019 23:23, Max Bond wrote: > There's nothing you can do with multmatrix() that you can't do with a > series of other transformations (rotate(), translate(), scale(), etc). That's not entirely true. You can skew transform with multmatrix, you cannot do that with the other transformations. In theory you could also do a perspective transformation (bottom row), but it is disabled in OpenSCAD. Carsten Arnholm

In fact, with a perspective transform, Max Bond code might avoid the expensive projection() by cutting a model slice (is this less expensive?) and transforming it directly with multmatrix(). Em seg., 16 de dez. de 2019 às 19:03, Carsten Arnholm <arnholm@arnholm.org> escreveu: > On 15.12.2019 23:23, Max Bond wrote: > > There's nothing you can do with multmatrix() that you can't do with a > > series of other transformations (rotate(), translate(), scale(), etc). > > That's not entirely true. You can skew transform with multmatrix, you > cannot do that with the other transformations. In theory you could also > do a perspective transformation (bottom row), but it is disabled in > OpenSCAD. > > Carsten Arnholm > >

Speaking of nerdsniping: You can perform a skew by composing rotate() with scale(). Doug. On Mon, Dec 16, 2019, at 7:01 PM, Carsten Arnholm wrote: > On 15.12.2019 23:23, Max Bond wrote: > > There's nothing you can do with multmatrix() that you can't do with a > > series of other transformations (rotate(), translate(), scale(), etc). > > That's not entirely true. You can skew transform with multmatrix, you > cannot do that with the other transformations. In theory you could also > do a perspective transformation (bottom row), but it is disabled in > OpenSCAD. > > Carsten Arnholm > > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >