Workflow
Use an image as evidence, not as an imaginary ruler
PurCad can use images to understand shape and context, then build a parametric interpretation. Known lengths and written constraints anchor the result so the generated model can be inspected and corrected.
Capture views that explain the geometry
Use even light, limited perspective and several views when possible. Include the mating face and any hidden clearance that matters. A ruler, known fastener or measured edge in the same plane gives the workflow a usable scale reference.
Pair visual context with measured facts
Upload the image and state which visible length is known. Describe the part's function, interfaces and manufacturing intent in text. PurCad uses the image as a reference, records the scale provenance and creates editable dimensions rather than claiming an exact reverse-engineered surface.
Compare silhouette and critical interfaces
Rotate the generated model beside the source image, inspect its overall bounds and use section or measurement tools on important edges. Review every default dimension that affects fit, then print a cheap fit sample before committing to the full part.
Perspective and hidden geometry remain uncertain
A single photograph cannot reveal occluded faces, lens distortion or precise depth. For tight fits, use multiple orthogonal images and direct measurements. Treat cosmetic resemblance and dimensional accuracy as separate acceptance criteria.