Can someone clarify the workflow stages and terminology of RC?
What is the difference between
Alignment>Align Images (arrow) button - (F6) Calculate poses for all inputs, and
Workflow>Start (same arrow symbol) buton - (F5) Create reconstruction using inputs?
Does F5 include F6 as a first step?
Does F6 produce what we call Point Cloud? Does F5 produce what we call Mesh?
Reconstruction>Normal Detail (F7)/Preview/High Detail - Create 3D model - does it produce what we call Mesh?
How does F7 relate to F5? both are termed Reconstruction.
Are tris and polys same thing? i.e. 3-sided polygons?
Does meshing consist basically of joining 3 adjacent point cloud dots to form a surface?
Colorize - (F8) Calculate a color for every triangle vertex - can this be applied to the point cloud, or only to the same points (vertexes) once meshed?
Texture - (F9) Calculate model texture - does this apply a scrap of the original photos to each triangle surface?
Wd be gd if somewhere a plain-language explanation of the whole process without assuming the jargon is already understood.
You have two options to go about creating a 3d reconstruction.
The manual mode where you run each step separate
The automatic mode (start button) that does it all in one.
It depends on your source images which process you should use.
For turntable photogrammetry the start button will likely work 98% of the time whereas with large objects, landscapes or complex objects you may want to go the manual route.
So yes, F5 does F6 as first step.
F6 produces a sparse point cloud that you can use to define the final reconstruction region (as you likely don’t want to reconstruct stuff outside the area of interest).
F5 simply runs alignment, reconstruction, texture one after the other with predefined settings.
Reconstruction: Preview is just that. It by default uses the sparse point cloud from alignment to give you an idea of the result.
Normal/High does a proper reconstruction. The difference is the resulting mesh density.
F5 does include F7 as part of the reconstruction.
tri = triangle. Which is, in fact, a polygon 
RC does not actually produce a dense point cloud like the competition does. It calculates depth maps for each input image and merges the depth maps to derive the final mesh.
colorize will calculate just the vertex color whereas texture does that plus the texture for the mesh.
Texturing is quite complex. It does not just take scraps from the original photos but merges colors from different input images together to create a more consistent texture.
Hope that helps
Thanks a lot for v comprehensive answer.