Questions about rendering to texture with Urho

Is it possible to render to texture once?
Is it possible to render to only part of a texture, to create atlases?

I want to render images once in real time and save them to atlases to be used by billboards.

hi
you can attach texture2d to Viewport, get RenderSurface and set manual update (for once render)

RenderSurface->SetUpdateMode(RenderSurfaceUpdateMode mode);

enum RenderSurfaceUpdateMode
{
SURFACE_MANUALUPDATE = 0,
SURFACE_UPDATEVISIBLE,
SURFACE_UPDATEALWAYS
};

Is it possible to render to only part of a texture, to create atlases?
it tricky say and find way how make this, but you may try

0. create hi-res RT (atlas)
1. create low-res rendertarget
2. render model into in low-res rendertarget
3. bind hi-res RT and use your own CustomCopyFramebuffer shader + ScissorsTest(or discard pixels by texCoords) to copy from low-res render target into selected place into Atlas.