Pencil Overlay

By Sid Porobic

This tutorial stemmed out of the need to produce attractive “hand made” images which are to be used when discussing architectural projects with clients and planning authorities alike. In my experience I have found a need to create relatively abstract images which are to serve the purpose of keeping a project open in the early stages of the design process.

The process itself is relatively simple. You will need software like Photoshop which supports layers and blending modes.  Although I personally use Photoshop you may find that open source image editing software could be perfectly adequate for this exercise. Download  Pencil Stroke and Base Image files for this tutorial here.

First you need to load your image file. It could be an image export directly from SketchUp. If that is the case you will need an image with shadows and no edges.

I use so called clay render done in Podium which sports occlusion and transparency.  I also use a rendered image with fully fledged material definition. Most of the preparation of the base image is in adding richness to the base image.

The things I usually go through are adding a small amount of noise and small amount of blur.  This allows me to control contrast in the image better, without creating artifacts. The other thing I do here is changing color either by adding additional layers of gradients or/and filter for manipulating tone mapping.

Second element you need is the image file containing pencil strokes. You either scan handmade pencil strokes or create the image in image editing software like Photoshop. I prepared such a file earlier in Photoshop.  You can further manipulate this file by changing Sharpness, Blur or Contrast. You also could add small amount of Noise if you wish.

These are the prepared base images using the methods described above:

Pre-prepared Base Image

Pencil Stroke Image

1. To begin with you need to open your base rendered image. I normally use Normal Blend mode for this image.

Step 1

2. Next thing you do is open your image with pencil strokes. You will need to make sure that the image is as big as or bigger than the base image.

Step 2

3. Position pencil image over base image.

Step 3

4. Now set the Blending mode to Soft Light.

Step 4

5. This gives it a nice rich contrast. Adjust the slider to anything between 30% and 60%, subject to your liking. One more thing you could do is selectively erase parts of the image pencil strokes in order to bring variation. If you choose to do that I suggest you use eraser tool with 50 % transparency to allow for smooth transition. Experiment until you feel you are comfortable with the end result.

Step 5

6. Once happy with the blend, Merge the image and then do a final contrast and curves adjustment.  There, you now have an attractive ‘hand made’ like image.  I hope you found this tutorial useful and you manage to incorporate it into your daily workflow.

Final Image

Further images using this Pencil Overlay method (base image clay render).

Bournemouth Clay Render

Technique Applied

Bournemouth Clay Render

Technique Applied

Thanks for reading this tutorial.

Cheers

Sid

S. Porobic (AKA ‘Sepo’) Chartered Architect.
Director of – S.Porobic Associates, Chartered Architects and Designers.
Director of – Renderclinic Ltd.
Member of Podium Development Team.
Lecturer at – The School of Arts, University of Northampton.

For any further information regarding Podium training or rendering services you can contact me on renderclinic@porobic.co.uk