How to measure full boats or larger areas with the Coded Target Letter Sheet Set

Letter Sheet Target Set

PhotoModeler supplies a set of coded targets for use in the marine industry for outlining boat decks. These are called the Letter Sheet Target set. They are available as pdf files or as a physical product made with a rubber-backing for ease of use.

PhotoModeler supports up to 999 unique target IDs, the Letter Sheet set is a sub-set of these.

Summary

Depending on the style and size of the boat, and how many photos are needed to capture it, a whole boat may be solved in a single project using just the Letter Sheet targets.

If this is not possible there are two main solutions:

  1. Modeling smaller sub-sections of the vessel and optionally merging them together.
  2. Creating additional targets using IDs above the Letter Sheet range.

Measuring larger areas

We recommend that when you start your work with PhotoModeler to outline boat decks that you start with small areas. Do not outline a whole boat as your first project. With experience gained, you may wish to work on larger areas. Note that you cannot print the Letter Sheet set multiple times and use it to cover larger areas. No target ID number can appear in different places on the boat in one project. Targets cannot be duplicated! See the approaches below.

Approaches for larger area outlining

Work with smaller areas and optionally merging

When you are starting out, to help learn the process, divide the boat into sub-sections and treat these as separate PhotoModeler projects and photo sets.  Each sub-section should be small enough that the area can be covered using the Letter Sheet target set.  For example, a swim platform, the bow area, and the stern could be done as three separate projects.

If you want to have these sub-projects combined there are two methods. You leave at least three targets fixed to the deck in the separate sub-projects. These three targets are used to align the projects in CAD after the export: see this tutorial video for guidance, or within PhotoModeler: see this video.

Add targets by printing more

You can print additional targets from within PhotoModeler. To ensure there is no overlap of the IDs, start with ID 214 and print targets with larger IDs only. You can choose your size, but the common choice is 6 targets per sheet (much like the Letter Sheets). You can then combine these in one project with the Letter Sheet Target set. As they are paper, you will have to tape them down to ensure they don’t move. See below for information on making more robust targets.

Making your own targets

If you find using paper targets is cumbersome, time consuming, and wasteful you may want to manufacture your own targets that have a rubber backing and a robust covering. If you make your own, you have more options on size and layout. We do recommend having at least 10 of the Letter Sheets (sheet A to J) in your set if you use the Coded Target Preset for automated set up of coordinate systems and scale.

You can use the Letter Sheet pdf files we provide or print additional pdf files from within PhotoModeler to pdf. Then use the pdf files to print on paper or plastic and then apply backings and coverings as needed.

If you will make targets yourself here are some guidelines:

  • Ensure to include white space around every target. The edge of the target pieces should not be close to the black band of the targets. Use the cut guides provided in the files.
  • Ensure each set you make has a unique set of ID numbers. No overlap of IDs within one set.
  • If you are covering or laminating the top sheet, ensure it is as matte as possible. There is a soft-matte available with some laminates. This helps if you are photographing in the sunshine.
  • Do not remove the PhotoModeler copyright from the full sheets.

We have a more detailed document, with material lists, which describes how we manufacture our targets. We provide this to customers with PhotoModeler licenses and a proven ability to use PhotoModeler. Please send us an email if you are interested.

 

Why this set size?

You may be curious why is the Letter Sheet Target set this size? Why is it not bigger?

The full set of target ids is quite large: 1 to 999. The Letter Sheet set pdf files and rubber-backed targets end with target #213 in the rounds set.

The Letter Sheet set is provided as a starting point. Many customers complete full projects using them, but there is the option to expand the set and to make your own as described above.

We sell our rubber-backed targets at cost. We are a software company that provides these to help you get started on your boat deck measurement journey. As you expand and / or get into more complex projects you have the option of expanding the target set under your own control. Do note that the PhotoModeler Coded Targets are unique and copyrighted but we provide permission for you to use and print your own if you do not change or remove the copyright (if you do want to white label your targets, please contact sales@photomodeler.com for options).