# Retain Block Definition in Section view from 3d to 2d drawings

Hello,
I just spoke with Ramon (from the visual arq team) about the possibility to use the Section view and retain the block definitions for the output geometry. We had a discussion and we went to the conclusion that there are no easy ways to do this. I just wonder if somebody has some ideas.

For example to draw and elevation from a series of 3d blocks and keep the geometry of windows inside a certain block, also in the 2d output.

If it´s achieavable, a customisation of the Section view in this sense would be able to undestand also difference between the same block in different points of view and positions. As the 3d block Object Instances are placed being part of the same Instace Definition, in 2d instead, being a projection there should be a differentiation ( maybe with a name block suffix) between blocks with similar projection plane (even if coming from the same Instance Defintion).

I am not sure if this can be really useful or it´s too complicated, but I wonder if this is achievable in theory. Basically to draw an elevation from certain facade 3d blocks, and and making a 2d block from the initial 3d block according to the projection planes, to differentiate the same initial block according to the elevation views.

In order to use 2D blocks for the elevation/section drawings, there are some important issues that need to be considered:

1. There are infinite number of view directions, so it is not possible to provide all possible 2D views for the window. I think most users will only provide the perpendicular 2D view. What VisualARQ should draw when the view is not perpendicular? The projected 3D block? The closest 2D block stretched?
2. Window leaves normally occlude objects that are behind it. 2D blocks are normally composed by 2D curves, so when using a 2D block for the elevation representation, objects behind the window will be visible. The only solution that I have found is perform the elevation (aka Make2D) using the 3D block. Then identify the projected curves that are generated from the 3D block, remove then, and place the 2D block in the right position. This is what we do in plan views. But elevation views adds a new problem: the same window may be partially occluded by a nearby object, so the 2D block will need to be processed again by a new Make2D in order to hide occluded curves.

In theory, this is achievable, but I don’t know if the result will be OK unless the user provides at least 8 different 2D representations at 45º each one.

Can you show me some examples of what you need to achieve?

Regards,

Enric