Thursday, April 21, 2016

Presentation Drawings in AutoCAD

Here's a first for this blog. Digital drawings. Presentation drawings, actually. I have many new hand drawings that I will be posting soon but I wanted to stop for a minute and post some rendered presentation drawings that I have recently done in my newly acquired AutoCAD LT2016 software. AutoCAD LT is perfect for the projects that I typically work which are, as a rule, fairly small (i.e.; houses, carriage house, etc.) and since I can draw and visualize fairly well by hand, I don't really need the 3D component that is part and parcel of full blown Revit / AutoCAD. Besides, the reason I think Revit sucks is if you are using it in the preliminary design phase of a project, it forces you to make quantifiable decisions early in the design stage that you're just not ready to make yet. 

All that being said, there are quite a few techniques to use  in creating drawings like this in AutoCAD LT2016. There is no software program that automatically creates the shadows and rendered elements here. What you need to bring to the table is your own graphic vocabulary that was developed based on your understanding of how to draw and present by hand. In other words, things like line weights, gradient shading, foreground and background elements and so forth are things that you will need to figure out for yourself. As if you were drawing by hand. Stop thinking of AutoCAD as BIM and start thinking of it as a set of pens. That is not inconsisent with anything you have learned about layer management. Think of pens as layers (BIM) and pens as pens (drawing representation). They don't have to be mutually exclusive. Take shadowing an elevations as an example. Shadows are simply developed by using the classic plan projection method by hand, you're just using a computer. Use a simple line work hatch pattern (ANSI31) when you you are rendering / applying your shadow hatch. Set the rotation angle to match the angle you are casting your shadows at. Solid and gradient hatches don't stack well on top of each other in lines merge or overwrite mode. So DRAW ORDER and HATCH EDIT  (foreground/background) are going to be very commonly used  commands in managing or manipulating your hatch applications. Gradient hatch patterns (colors 250-255) were used for all of the gradient and solid grey tone rendering shown on these drawings. Gradient tones can be tricky, especially over large areas of the drawing because for gradient tones to work in hatch they almost always need to go on as a single application.

These drawings use a fine presentation level pen & ink vocabulary and compositional drawing techniques that I have developed by hand over many years. And since AutoCAD really hates excessive hatching, you kind of have to trick it sometimes by using a simple hatch pattern and then using hatch edit to change to your gradient pattern. Much less memory intensive that way.

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